November 2014 - Boost-users - lists.preview.boost.org

[interprocess] Determine size of managed_shared_memory
by Kai Benndorf 12 Oct '19

12 Oct '19

Hi all, I want to create a managed_shared_memory in exactly the size I needed. Therefore I do something like this: size = sizeof( common_managed_shared_memory ); size += sizeof( MyClassInSharedMem ); managed_shared_memory segment(create_only, "name", size ); MyClassInSharedMem allocates itself some memory by segment->allocate(). I added this also to the size, but get a boost::interprocess::bad_alloc exception on allocating this additional memory. Are there some magic bytes I forgot to add? Many thanks in advance Kai

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[Range, Phoenix] What am I missing...
by Robert Jones 25 Apr '17

25 Apr '17

Hi Folks Can anyone explain the output of this program... #include <iostream> #include <boost/range/algorithm/copy.hpp> #include <boost/range/counting_range.hpp> #include <boost/range/adaptor/reversed.hpp> #include <boost/range/adaptor/transformed.hpp> #include <boost/phoenix/bind/bind_function.hpp> #include <boost/phoenix/core/argument.hpp> int f( int i ) { return i * 2; } int main( ) { using boost::adaptors::reversed; using boost::adaptors::transformed; using boost::counting_range; using boost::copy; using boost::phoenix::arg_names::_1; copy( counting_range( 1, 5 ) | reversed | transformed( f ), std::ostream_iterator<int>( std::cout, " " ) ); std::cout << std::endl; copy( counting_range( 1, 5 ) | reversed | transformed( bind( f, _1 ) ), std::ostream_iterator<int>( std::cout, " " ) ); std::cout << std::endl; } Which is... 8 6 4 2 1768406272 1768406272 1768406272 1768406272 I'm using Gcc 4.6.2 & Boost 1.53 Thx All.

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[statechart] Passing parameters from event to State Local Storage
by Christophe Bourez 16 Nov '16

16 Nov '16

I need to maintain a parameter into the state local storage. This parameter is initially contained in the event that causes the transition to the target state. I give hereafter a small illustrative example. typename sc = boost::statechart; class EvTest : public sc::event<EvTest> { public: EvTest(std::size_t val) : value(val) {} std::size_t getValue() const { return this->value; } private: std::size_t value; }; class MyStateMachine; class StSource; class StTarget; class StSource : public sc::simple_state<StSource, MyStateMachine> { public: typedef sc::custom_reaction<EvTest> reactions; sc::result react(const EvTest &event) { // How to pass event.getValue() to the target state ? transit<StTarget>(); } }; class StTarget : public sc::simple_state<StTarget, MyStateMachine> { public: StTarget(std::size_t val) : val(value) {} private: std::size_t value; }; Thanks, Christophe

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Some strange boost headers errors
by alfonso santimone 15 May '15

15 May '15

Hi guys, i'm a boost newbie. I've got to include boost libraries in the include path of a VisualStudio 2012 project. When i try to compile i have all these errors. Every errors is related to missing headers ( boost ones and even standard Win ones ) and to synthax errors depending on missing headers i guess. Do someone have any idea on what's wrong here? I just post here a few lines of errors, but the other ones are all of the same kind Error 1 error C2061: syntax error : identifier 'boost' C:\boost_1_57_0\boost\core\ checked_delete.hpp 24 1 csound~ Error 2 error C2059: syntax error : ';' C:\boost_1_57_0\boost\core\checked_delete.hpp 24 1 csound~ Error 3 error C2449: found '{' at file scope (missing function header?) C:\boost_1_57_0\boost\core\checked_delete.hpp 25 1 csound~ Error 4 error C2059: syntax error : '}' C:\boost_1_57_0\boost\core\checked_delete.hpp 67 1 csound~ Error 5 error C2054: expected '(' to follow 'using' C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\include\cstddef 19 1 csound~ Error 6 error C2061: syntax error : identifier 'using' C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\include\cstddef 19 1 csound~ Error 7 error C2061: syntax error : identifier 'boost' C:\boost_1_57_0\boost\smart_ptr\detail\sp_nullptr_t.hpp 23 1 csound~ Error 8 error C2059: syntax error : ';' C:\boost_1_57_0\boost\smart_ptr\detail\sp_nullptr_t.hpp 23 1 csound~ Error 9 error C2449: found '{' at file scope (missing function header?) C:\boost_1_57_0\boost\smart_ptr\detail\sp_nullptr_t.hpp 24 1 csound~ Error 10 error C2059: syntax error : '}' C:\boost_1_57_0\boost\smart_ptr\detail\sp_nullptr_t.hpp 41 1 csound~ Error 11 error C2054: expected '(' to follow 'using' C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\include\cstdlib 19 1 csound~ Error 12 error C2061: syntax error : identifier 'using' C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\include\cstdlib 19 1 csound~ Error 13 error C2061: syntax error : identifier 'abort' C:\Program Files (x86)\Microsoft Visual Studio many thanks in advance bests alfonso www.elgallorojorecords.com soundcloud.com/alfonsosantimone www.facebook.com/alfonsosantimone

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Re: [Boost-users] lexical_cast between double and string slow in Visual Studio 2013
by David Roberts 07 May '15

07 May '15

> That issue is unknown. I'd really appreciate the investigation. I have done some more investigation, and there are two factors that only cause the slowness when they both occur together. > Try excluding the lexical_cast from test, I have a feeling that this is only MSVC related issue: > > #include <sstream> > #include <string> > > int main (int, char **) > { > for (double count = 0.0; count < 1000000.0; count += 1.41) > { > std::stringstream ss; > ss << count; > std::string result = std::move(ss.str()); > ss.str(std::string()); > > ss << result; > ss >> count; > } > > return 0; > } > Running your test program does not exhibit the problem. It runs in around 3 seconds on my machine when built with either Visual Studio 2010 or Visual Studio 2013. However, changing it very slightly to match more closely what lexical_cast does internally does recreate the problem: #include <sstream> #include <string> int main (int, char **) { for (double count = 0.0; count < 1000000.0; count += 1.41) { std::stringstream ss; ss.unsetf(std::ios::skipws); ss.precision(17); ss << count; std::string result = std::move(ss.str()); ss.str(std::string()); ss << result; ss >> count; } return 0; } The effect of setting the precision to 17 is that lots of 9s appear in the string representations. (The number 17 is what boost::detail::lcast_get_precision(double*) chooses.) Without the precision call the contents of the string called result start off like this: 0 1.41 2.82 4.23 5.64 7.05 8.46 9.87 11.28 12.69 With precision set to 17 they start off like this: 0 1.4099999999999999 2.8199999999999998 4.2299999999999995 5.6399999999999997 7.0499999999999998 8.4599999999999991 9.8699999999999992 11.279999999999999 12.69 This happens for both Visual Studio 2010 and Visual Studio 2013. Then the next difference is that Visual Studio 2013 spends a lot longer handling all the extra 9s. Changing the program so that the double is converted to a string using std::stringstream without a precision call and then back to double using lexical_cast takes about 3 seconds for both Visual Studio 2010 and Visual Studio 2013. It is the combination of having all the extra 9s to parse and using Visual Studio 2013 that makes the test using lexical_cast to go both ways slow. Both Visual Studio 2010 and Visual Studio 2013 do the conversion by calling std::num_get<char,std::istreambuf_iterator<char,std::char_traits<char> > >::do_get() which then calls a function called _Stodx() which is implemented in xstod.c. This function is very different for the two versions. In Visual Studio 2010 it's a relatively thin wrapper around the C function strtod(). In Visual Studio 2013 _Stodx() has got a completely new implementation that's generated by #including xxstod.h with some macros defined. The original C function strtod() is much faster than the new _Stodx() when there are lots of 9s at the end of the strings being parsed. This modification to the program: #include <sstream> #include <string> #include <stdlib.h> int main (int, char **) { for (double count = 0.0; count < 1000000.0; count += 1.41) { std::stringstream ss; ss.unsetf(std::ios::skipws); ss.precision(17); ss << count; std::string result = std::move(ss.str()); ss.str(std::string()); ss << result; char *endptr; count = strtod(ss.str().c_str(), &endptr); } return 0; } has a runtime of about 3 seconds even though it's got to cope with all the 9s. I guess only someone from Microsoft or Dinkumware could comment on why _Stodx() was reimplemented. But the other thing is that by setting precision to 17 lexical_cast is bloating the string representations of the doubles with lots of 9s in both Visual Studio 2010 and Visual Studio 2013. Setting precision to 15 instead prevents this, and makes the original test run faster even with Visual Studio 2013 (about 4 seconds rather than 10). Regards, David

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[boost.geometry] buffer distance strategies
by gchlebus 09 Mar '15

09 Mar '15

Hi, I am wondering whether it would be possible to achieve anisotropic buffering (distances in neg x, pos x, neg y, pos y can have different values) of a polygon using the buffer function with custom-implemented distance strategy. What I want to achieve is presented on the figure 2-b in the following paper: http://itcnt05.itc.nl/agile_old/Conference/mallorca2002/proceedings/posters… I would be grateful to hear from you whether it is doable, and if positive, how one could implement such a custom distance strategy. Best, -- View this message in context: http://boost.2283326.n4.nabble.com/boost-geometry-buffer-distance-strategie… Sent from the Boost - Users mailing list archive at Nabble.com.

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Statechart serialization
by mbrodeur65 04 Mar '15

04 Mar '15

Hi, I'm looking for a solution to serialize boost::statechart objects. I'm aware that this feature is on the statechart library todo list but was wondering if there are any workaround to achieve this with the latest boost release (1.34) ? thanks for your help ! mbrodeur65 -- View this message in context: http://www.nabble.com/Statechart-serialization-tf4131326.html#a11749139 Sent from the Boost - Users mailing list archive at Nabble.com.

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[interprocess] Bizarro File Names (Windows)
by Aaron_Wright＠selinc.com 28 Jan '15

28 Jan '15

I have a service that is running in Windows Server 2008 R2 SP1 that uses shared memory. It runs fine for a month or so, but then stops working correctly. When I check the C:\ProgramData\boost_interprocess\*\ folder, I get a bunch of weird file names, such as: 88C861CD6DE2CF01EBA2F0CC1200D001A4070000EBFFFFFF 88C861CD6DE2CF01EBA2F0CC1200D001A4070000ECFFFFFF 88C861CD6DE2CF01EBA2F0CC1200D001A4070000EDFFFFFF 88C861CD6DE2CF01EBA2F0CC1200D001A4070000EEFFFFFF 88C861CD6DE2CF01EBA2F0CC1200D001A4070000EFFFFFFF 88C861CD6DE2CF01EBA2F0CC1200D001A4070000F0FFFFFF 88C861CD6DE2CF01EBA2F0CC1200D001A4070000F1FFFFFF 88C861CD6DE2CF01EBA2F0CC1200D001A4070000F2FFFFFF 88C861CD6DE2CF014B04F3CC1200D001A40700000AFFFFFF 88C861CD6DE2CF014B04F3CC1200D001A40700000BFFFFFF 88C861CD6DE2CF014B04F3CC1200D001A40700000CFFFFFF 88C861CD6DE2CF014B04F3CC1200D001A40700000DFFFFFF ... (and so on) These are not even close to the names that are supposed to be used. They seem to increment a bit, then shift slightly, and start incrementing again. When I restart the service I get similar named files and patterns, and my services crashes because it can't grow shared memory (presumably because the file names are not correct). I have to restart the box in order to get the correct behavior. Has anyone seen this behavior before? --------------------------------------------------------- Aaron Wright

1 1

[multi state machine/ MSM] execute_queued_events
by Steve Hickman 26 Jan '15

26 Jan '15

In the MSM doc section "Enqueueing events for later processing", you state that "Calling execute_queued_events() will then process all enqueued events (in FIFO order)." You also said in a previous post that MSM is not thread safe, thus requiring an external mechanism to insure thread safety. I don't see a mechanism to execute a single event at a time, which would be preferable if I have to lock the queue while processing events. Having said that, a cursory examination of the "execute_queued_events" code makes me think it only processes one event per call. Which is correct? Is the documentation correct that it actually processes all queued events? If not, can the documentation be corrected? If so, is there a publicly usable call to process a single queued event? If there is no publicly available call for processing a single queued event, how do you recommend processing queued events in a thread safe manner that won't lock the queue for extended periods of time?

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[endian] Boost.Endian library added for 1.57.0
by Beman Dawes 14 Dec '14

14 Dec '14

The library provides integer and floating point types and conversion functions for portable byte ordering regardless of processor endianness. Although the primary uses are for file or network I/O, it is also useful for unaligned integers or floats, or for 3, 5, 6, and 7 byte integers. The library's predecessors have been in use for thirty years and developed independently multiple times. The repository is https://github.com/boostorg/endian The documentation is online at https://boostorg.github.io/endian/ See https://boostorg.github.io/endian/index.html#Release-history for changes since the Formal Review. No need to report "Inspection Report" problems; those will be cleaned up before 1.57.0 ships. Please do report any other problems or concerns, since the time between now and when the 1.57.0 beta ships in effect acts a mini-review period. If anyone has access to a big-endian platform with a modern C++ compiler, please, please run the endian test suite and report the results. All testing and use in recent years has been on little-endian platforms, so big-endian platform testing is a worry. Thanks for you patience, --Beman

3 2

boost MSM
by Raj Sambasivan 10 Dec '14

10 Dec '14

Hi Christophe, I have been using boost msm, i have two state machines each with around 30 transitions / 4 regions , no submachine etc for now... it perfectly fits the bill on what im trying to do, thanks for the great library, one issue i face is ,the debug build takes for ever to compile and the size is very big (the optimized one with no debug symbol compiles pretty fast) and when errors happens the compiler (template barf) goes for pages and pages .. any hints on this please? thanks -raj

4 5

[Boost.Test] unexpected behavior after std::system(...)
by contini.mailing＠gmail.com 09 Dec '14

09 Dec '14

Hi, I'm using boost 1.57 with gcc 4.7.2 on a debian wheezy. I'm testing an external program that has a non-zero return code and i'm experiencing an unexpected behavior of Boost.Test library. If the test below is linked statically (commenting the first line of course) everything works fine and all the three tests are executed. If the test below is linked dynamically i get the following output: test0 test1 unknown location(0): fatal error in "test1": child has exited; pid: 32314; uid: 1000; exit value: 4 (here program hangs forever and the third test is never executed) Defining the environment variable BOOST_TEST_CATCH_SYSTEM_ERRORS=No circumvents the problem. But i don't want to define it on all of the team member's computers and test machines. This can be considered a boost bug? #define BOOST_TEST_DYN_LINK #define BOOST_TEST_MODULE test_module #define BOOST_TEST_IGNORE_NON_ZERO_CHILD_CODE #include <boost/test/unit_test.hpp> #include <stdlib.h> BOOST_AUTO_TEST_CASE( test0 ) { std::system("echo \"test0\";exit 0;"); } BOOST_AUTO_TEST_CASE( test1 ) { std::system("echo \"test1\";exit 1;"); } BOOST_AUTO_TEST_CASE( test2 ) { std::system("echo \"test2\";exit 2;"); } Any help is appreciated.

2 1

[Boost.SIMD] Interest in library
by dariomt＠gmail.com 05 Dec '14

05 Dec '14

Hi, I'm interested in trying out Boost.SIMD. Where can I download the latest stable version? Any idea when it might get proposed for Boost review? I think it would be beneficial if it is added to the Boost Incubator until then. Also, in http://meetingcpp.com/tl_files/mcpp/slides/12/simd.pdf slide 36 I see mention of a vectorized Thomas Tri-diagonal Solver. I thought the data dependency made the algorithm unfeasible for vectorization, so I'm *very* interested to learn how Boost.SIMD helps in this case. Is there more information available about this? Thanks for working in a library that shows a lot of potential.

4 3

Fusion Move Semantics
by Ovanes Markarian 04 Dec '14

04 Dec '14

Hi! I would like to ask does fusion supports move semantics, or are all the values going to get copied. I use C++11 (clang with libstdcxx) and boost 1.54 (but can upgrade). In my use case I have boost::fusion::map and was wondering, that in case of moving of that map, is it going to forward the move call to contained values or not. Many thanks for help, Ovanes

3 2

Error "Used Uninitialized" in boyer_myrvold_impl.hpp
by wanglurg 02 Dec '14

02 Dec '14

Hi, guys, I'm a new boost graph library user. I met an error when using boyer_myrvold_planar_test() function in Boost_1_55_0 to generate the kuratowski subgraph. Error message is listed as follows: ./boost/graph/planar_detail/boyer_myrvold_impl.hpp:1545:11 error: 'z' may be used uninitialized in this function. I added a "Wno-maybe-uninitialized" flag to Makefile to remove this error temporarily, but it's not a good method. I'm looking for a better way to fix this. Does anyone encounter the same case? Best regards, Lu Wang -- View this message in context: http://boost.2283326.n4.nabble.com/Error-Used-Uninitialized-in-boyer-myrvol… Sent from the Boost - Users mailing list archive at Nabble.com.

2 2

Reverse for loop with boost::adaptors::reverse crashes
by Filip Konvička 28 Nov '14

28 Nov '14

Hi, I was trying to replace BOOST_REVERSE_FOREACH with the standard range-based for loop. #include <boost/range/adaptor/reversed.hpp> #include <boost/foreach.hpp> #include <vector> #include <iostream> std::vector<int> getv() { return std::vector<int>{1,2,3}; } int main(int argc, char* argv[]) { // works fine: BOOST_REVERSE_FOREACH(int i, getv()) std::cout << i << std::endl; // crashes: for(int i : boost::adaptors::reverse(getv())) std::cout << i << std::endl; return 0; } Maybe this is basic C++ I should understand; it looks like the temporary vector returned by getv() gets destroyed in the 2nd loop too soon. I was wondering whether the adaptor could warn me that I'm using it in a wrong way (the code looks so nice and compiles cleanly...). Thanks, Filip

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Boost.Log: default sink auto flush
by Mathias Gaunard 27 Nov '14

27 Nov '14

It would be very useful if the default sink could be made to auto flush. Is there any way to do this? I do not want to add a new sink, since the default sink cannot be replaced.

1 0

Unable to build universal binary on Mac OS X
by Kevin Molcard 27 Nov '14

27 Nov '14

Hi all, I am trying to compile boost on Mac OS X 10.9.5 for 32 and 64 bit. I am using the following command: ./b2 link=static threading=multi architecture=x86 address-model=32_64 I get the following error message: darwin.compile.c++.pch bin.v2/libs/math/build/darwin-4.2.1/release/address-model-32_64/architecture-x86/link-static/threading-multi/../src/tr1/pch.hpp.gch clang: error: cannot use 'precompiled-header' output with multiple -arch options "g++" -x c++-header -O3 -finline-functions -Wno-inline -Wall -gdwarf-2 -fexceptions -arch i386 -arch x86_64 -DBOOST_ALL_NO_LIB=1 -DBOOST_BUILD_PCH_ENABLED -DNDEBUG -I"." -I"libs/math/src/tr1" -c -o "bin.v2/libs/math/build/darwin-4.2.1/release/address-model-32_64/architecture-x86/link-static/threading-multi/../src/tr1/pch.hpp.gch" "libs/math/build/../src/tr1/pch.hpp" ...failed darwin.compile.c++.pch bin.v2/libs/math/build/darwin-4.2.1/release/address-model-32_64/architecture-x86/link-static/threading-multi/../src/tr1/pch.hpp.gch... Then 144 targets are skipped. Does anyone knows how to fix this? Thanks in advance Kevin

2 2

[review] [sort] Sort library review manager results
by Edward Diener 27 Nov '14

27 Nov '14

This is the results from the recent review of the Sort library of Steven Ross. First I would like to thank all those who made comments during the review, whether or not they officially gave a final Yes or No vote to whether the Sort library should be accepted as a Boost library. This list includes: Niall Douglas, Julian Gonggrijp, Phil Endecott, Vladimir Prus, Mathias Gaunard, Jeremy Murphy, Peter Dimov, Robert Ramey, Adam Walling, Anthony Polukhin, Phil Endecott, Paul Bristow, Thijs (M.A.) van den Berg Dupuis Etienne, and Frank Gennari If I have missed anyone I do apologize. Secondly I would like to thank Steven Ross for patiently answering all of the review comments to the best of his ability. My tally of Yes and No votes for acceptance are: Yes votes (5) : Niall Douglas ( conditional ), Julian Gonggrijp ( conditional ), Frank Gennari, Phil Endecott, Paul Bristow. No votes (3) : Vladimir Prus, Adam Walling ( conditional ), Anthony Polukhin I believe the condtional Yes vote from Julian Gonggrijp was completely met in the discussions of issues with Steven Ross and the conditional Yes vote from Niall Douglas was almost completely met in the discussion with Steven Ross about the issues mentioned, and enough to maintain his Yes vote. I want to also mention that the conditional No vote by Adam Walling has an implied Yes vote to it if the Sort library were one among other sort implementations. Since my final decision is not entirely based on the Yes and No votes I want to adumbrate some of the major issues brought up by the review without necessarily focussing on every one of the people who brought them up initially, as well as my own reactions to them as Review Manager. 1) The first major issue was whether a library whose basic merit lies in its algorithm and its speed/space constraints needs better theoretical backing. A number of reviewers discussed this after it was brought up. I tend to agree with reviewers that while the best theoretical basis is always desirable, it is not necessary for a Boost library whose empirical evidence can be and has been measured by its implementor and can be measured by any user. Furthermore Steven Ross has provided an extensive discussion in his documentation, as well as his original paper, about the theoretical merits of his technique. While much of this discussion is probably beyond the understanding of any but sorting experts and afficionados enough of it adequately explains the basic ideas behind SpreadSort for those who understand and have knowledge of basic sorting ideas and popular sorting techniques. 2) An important issue is the need for the Sorting library to provide extensive timing charts/tables comparing SpreadSort to at least std::sort ( and possibly other popular mainstream sorts ) with both different numbers of sort keys and different initial unsorted distributions. Steven Ross has been providing these charts/tables in the 'develop' branch of the library. 3) Connected to the previous issue is that a number of reviewers asked for better documentation on the conditions in which SpreadSort will show a marked improvement in speed compared to std::sort, as well as any condition(s) where SpreadSort performs worse than std::sort. While Steven Ross has explained that generally SpreadSort will fall back to using std::sort for some cases ( low N ), I too feel that the documentation needs to be more extensive for the average user in attempting to delineate the conditions where SpreadSort works best. 4) A really important issue discussed by a number of reviewers involves the creation of a synthetic radix, where most users of sorting algorithm are used to comparison based sorting functors. While the documentation provides information on the various individual sorts, as well as examples, I also feel that a discussion in the documentation of how to use SpreadSort when sorting structs/classes with multiple keys of different types would be invaluable. In other words, what and if are the common techniques for using SpreadSort with complicated keys which, when using comparison-based sorting, can be represented fairly easily be a functor. 5) Niall Douglas brought up the issue of exception guarantees when using SpreadSort, and I concur. The documentation should be stronger specifying what happens during the sorting algorithms if an exception occurs and/or does the sorting algorithm itself ever throw any exceptions and, if so, under what conditions. Steven Ross mentioned that he is adding exception guarantee information to his docs. 6) Many reviewers did not like the idea that the library should be called Sort when it is basically implementing a single sorting algorithm called SpreadSort. Alternate suggestions are: a) The library should be called SpreadSort. b) The library can be called Sort only if other sorting algorithms are added to it. c) The library can be called Sort with the proviso that it serves as a general library for sorting algorithms potentially added to it in the future. d) The library should be part of the Boost Algorithm library. Steven Ross mentioned other potential sorting implementations as part of the Sort library, under that general name, but all providing a good deal of extra work. These included a copy-based stable sorting algorithm, an LSD radix sorting, and an OpenMP based parallel implementation. Other reviewers mentioned some of the same types of sorting implementations and a few reviewers remarked that they also have created sorting implementations of their own. While I will give my own view at the end, I would like to mention here that I strongly believe that each sorting implementation needs to be reviewed separately for acceptance into Boost and never automatically added to a general library, whether it be called Sort or Algorithm or whatever. 7) Random issues brought up in comments I will mention, which have importance but which I do not believe are absolutely intrinsic yet still might be considered. a) C++11 techniques in general and inline namespaces in particular. b) A version that can work with less than random access. c) Optimizations for small sets of data ( Steven Ross has already addressed this to an extent in the 'developer' branch of the library ). d) Possible documentation of using SpreadSort as a subsort for parallel sorting techniques and possible discusion in the docs about SpreadSort and parallel sorts. e) General O() information in docs. f) SpreadSort examples hoisted directly into docs using Quickbook technique and updating the Spreadort docs to use Quickbook. Review Result: Based on the voting for acceptance or not, based on the discussions during the review period, and based on Steven Ross's responses, I have decided that Steven Ross's library should be accepted into Boost. My main reason for my decision, aside from the votes and comments and specific issues discussed, is twofold: 1) There is a general consensus that Steven Ross has an excellent understanding of sorting techniques and algorithms and will support and refine his library for the benefit of programmers. 2) The empirical tests show that SpreadSort offers an improvement over std::sort, significantly in the area of large data sets, and this could be a major benefit to programmers. I do not know if the review manager has a say in this but based on the remarks of the reviewers I would like to see the library as accepted be named 'SpreadSort' rather than just 'Sort'. I do think that Boost can have a library called 'Sort' but I agree with the general consensus that a 'Sort' library needs more than one type of sorting algorithm. I would like to see other people, who mentioned in the reviews/comments that they have their own sorting implementation, also submit their own implementations to Boost and, if this happens and they are accepted, I can see combining them with 'SpreadSort' into a general Boost sorting library called 'Sort' in the future.

1 0

Boost not compiling with arm-cross-compiler
by ustulation 27 Nov '14

27 Nov '14

{Ubuntu 14.04 64 bits, arm-g++ compiler 4.9 one that comes with google's ndk r10c) (The compiler has --sysroot pointing to platform android-14, and -march=armv7-a) on using arm cross-compiler for compiling boost I get the following error in "*socket_ops.ipp*": *<1> for all function (templates) of this type:* template <typename SockLenType> inline int call_getsockname(SockLenType msghdr::*, socket_type s, socket_addr_type* addr, std::size_t* addrlen) { SockLenType tmp_addrlen = (SockLenType)*addrlen; int result = ::getsockname(s, addr, &tmp_addrlen); *addrlen = (std::size_t)tmp_addrlen; return result; } /some-path/thirdparty/boost/boost_1_55_0_Android/boost/asio/detail/impl/socket_ops.ipp:1639: error: invalid conversion from 'int*' to 'socklen_t* {aka unsigned int*}' [-fpermissive] int result = ::getsockname(s, addr, &tmp_addrlen); ^ On changing the line to: int result = ::getsockname(s, addr, (socklen_t*)tmp_addrlen); it compiles fine ofcourse but i don't know if this is what is to be done. *<2> And in "mapped_region.hpp": /some-path/thirdparty/boost/boost_1_55_0_Android/boost/interprocess/mapped_region.hpp:49: error: sys/shm.h: No such file or directory # include <sys/shm.h> //System V shared memory... ^ * and points to: # if defined(BOOST_INTERPROCESS_XSI_SHARED_MEMORY_OBJECTS) # include <sys/shm.h> //System V shared memory... # endif in that file. Here are the flags in my user-config.jam file: using gcc : android : @AndroidNDKSrcDir@/bin/arm-linux-androideabi-g++ : <archiver>@AndroidNDKSrcDir@/bin/arm-linux-androideabi-ar <compileflags>-fexceptions <compileflags>-frtti <compileflags>-fPIC <compileflags>-std=c++11 <compileflags>-ffunction-sections <compileflags>-funwind-tables <compileflags>-D__ARM_ARCH_5__ <compileflags>-D__ARM_ARCH_5T__ <compileflags>-D__ARM_ARCH_5E__ <compileflags>-D__ARM_ARCH_5TE__ <compileflags>-Wno-psabi <compileflags>-march=armv5te <compileflags>-mtune=xscale <compileflags>-msoft-float <compileflags>-mthumb <compileflags>-Os <compileflags>-fomit-frame-pointer <compileflags>-fno-strict-aliasing <compileflags>-finline-limit=64 <compileflags>-I@AndroidNDKSrcDir@/include/c++/4.9 <compileflags>-Wa,--noexecstack <compileflags>-DANDROID <compileflags>-D__ANDROID__ <compileflags>-DNDEBUG <compileflags>-O2 <compileflags>-g <compileflags>-I@AndroidNDKSrcDir@/sysroot/usr/include <architecture>arm <compileflags>-fvisibility=hidden <compileflags>-fvisibility-inlines-hidden <compileflags>-fdata-sections <cxxflags>-D__arm__ <cxxflags>-D_REENTRANT <cxxflags>-D_GLIBCXX__PTHREADS ; *What is the way forward for those two errors - <1> and <2> above ?* -- View this message in context: http://boost.2283326.n4.nabble.com/Boost-not-compiling-with-arm-cross-compi… Sent from the Boost - Users mailing list archive at Nabble.com.

2 1

[boost::accumulators::impl::immediate_mean_impl<Sample, Tag>::operator()<Args>] c++/cli
by It neophyte 26 Nov '14

26 Nov '14

Hi While computing a variance on my dataset, I end up with: error C2677: binary '+' : no global operator found which takes type 'System::Object ^const ' (or there is no acceptable conversion) The error message point to the line 65 of mean.hpp (see below piece of code). Can someone explain what's going wrong? Thanks template<typename Args> // line 59 void operator ()(Args const &args) //line 60 { // line 61 std::size_t cnt = count(args); // line 62 this->mean = numeric::fdiv( // line 63 (this->mean * (cnt - 1)) + args[parameter::keyword<Tag>::get()] // line 64 , cnt // line 65 ); // line 66 } // line 67 my code: #pragma once#include "stdAfx.h"#include "math.h"#include <boost/accumulators/accumulators.hpp>#include <boost/accumulators/statistics/stats.hpp>#include <boost/accumulators/statistics/variance.hpp> ..... accumulator_set< double, stats<tag::variance> > acc_variance; DataRow^i; for (int i=1;i-1<dbdataset->Rows->Count-1;i++){ dbdataset->Rows[i-1]["DataRet"]=log(System::Convert::ToDouble(dbdataset- >Rows[i-1]["Pop"])/System::Convert::ToDouble(dbdataset->Rows[i]["Pop"])); acc_variance(dbdataset->Rows[i-1]["DataRet"]); lblvol->Text = Convert::ToString(sqrt(variance(acc_variance))); }

1 0

boost::filesystem::extension crashes on Linux
by Jürgen Simon 26 Nov '14

26 Nov '14

Hello, I have a crash with boost 1.56 that happens on SUSE Linux for me (uname -a : Linux r105b.meteo.uni-bonn.de 3.7.10-1.28-desktop #1 SMP PREEMPT Mon Feb 3 14:11:15 UTC 2014 (c9a2c6c) x86_64 x86_64 x86_64 GNU/Linux) The crash happens in filesystem::extension() when listing a file from the following directory: $ ls -la core total 29802736 drwxr-xr-x 2 simon users 4096 Nov 25 14:40 . drwxr-xr-x 7 simon users 4096 Nov 25 15:05 .. -rw-r--r-- 1 simon users 30517985568 Nov 14 2013 rico.out.xy.core.nc As you can see there’s only one file in there that ends on “.nc”. The following code crashes on Linux but works fine on OSX (with the same data): fs::path f = fs::path(source_path); std::string extension = fs::extension(f); The GDB backtrace is: #0 0x00007fffe09403d5 in raise () from /lib64/libc.so.6 #1 0x00007fffe0941858 in abort () from /lib64/libc.so.6 #2 0x00007fffe11438cd in __gnu_cxx::__verbose_terminate_handler() () from /usr/lib64/libstdc++.so.6 #3 0x00007fffe11419c6 in ?? () from /usr/lib64/libstdc++.so.6 #4 0x00007fffe11419f3 in std::terminate() () from /usr/lib64/libstdc++.so.6 #5 0x00007fffe1141c1e in __cxa_throw () from /usr/lib64/libstdc++.so.6 #6 0x00007fffe119336d in std::__throw_runtime_error(char const*) () from /usr/lib64/libstdc++.so.6 #7 0x00007fffe115e844 in std::locale::facet::_S_create_c_locale(__locale_struct*&, char const*, __locale_struct*) () from /usr/lib64/libstdc++.so.6 #8 0x00007fffe1153774 in std::locale::_Impl::_Impl(char const*, unsigned long) () from /usr/lib64/libstdc++.so.6 #9 0x00007fffe11547af in std::locale::locale(char const*) () from /usr/lib64/libstdc++.so.6 #10 0x00007ffff753036f in boost::filesystem::path::codecvt() () from /usr/local/lib/libboost_filesystem.so.1.55.0 #11 0x00007ffff75307ff in boost::filesystem::path::begin() const () from /usr/local/lib/libboost_filesystem.so.1.55.0 #12 0x00007ffff7530f88 in boost::filesystem::path::compare(boost::filesystem::path const&) const () from /usr/local/lib/libboost_filesystem.so.1.55.0 #13 0x00007ffff75310f4 in boost::filesystem::path::extension() const () from /usr/local/lib/libboost_filesystem.so.1.55.0 #14 0x0000000000448adb in boost::filesystem::extension (p=...) at /usr/local/include/boost/filesystem/convenience.hpp:36 Any ideas how to circumvent this problem? Jürgen

1 0

[Boos-users][Boost.accumulators.Statistics.variance.hpp]: How to Compute Sample Volatility on data stored in DataTable
by It neophyte 26 Nov '14

26 Nov '14

Hi Do you know how can I compute a sample volatility of the returns held in a particular column of my db Datable? Any code illustration would be appreciated. Best,

1 0

[accumulators->Statistics] How to Compute Sample Volatility_c++ Windows Form app
by It neophyte 25 Nov '14

25 Nov '14

Dear All Do you know how can I compute the sample volatility (sqrt(variance)) of the returns held in my Datable? For information, my db object contains a column "Return" which has been filled with values. DataTable^db=gcnew DataTable(); Thanks in advance Heron

1 0

Re: [Boost-users] fusion: map
by MM 25 Nov '14

25 Nov '14

Hi, At the point of _defining_ a fusion::map, do the key types have to be known or can they just be forward declared at that point? Rds,

1 0

Phoenix V2
by Mathieu Champlon 25 Nov '14

25 Nov '14

Hello, Has Phoenix V2 been removed from Boost 1.57 ? I used to be able to find it under boost/spirit/home/phoenix but it seems it's no longer the case. Thanks, MAT.

3 5

Re: [Boost-users] lockfree::spsc_queue & move semantics
by Thomas Danckaert 24 Nov '14

24 Nov '14

From: Bjorn Reese <breese(a)mail1.stofanet.dk> Subject: Re: [Boost-users] lockfree::spsc_queue & move semantics Date: Mon, 10 Nov 2014 20:39:24 +0100 > On 11/09/2014 09:49 PM, Thomas Danckaert wrote: >> I'd like to use a spsc_queue of unique_ptr's to bigger objects, to >> transfer ownership between threads. That way, I can create/allocate an > > This limitation inherited from atomic, and I am afraid that it is a > bit more complicated than adding a move constructor. Fortunately, > there > is a C++ proposal to address the problem: > > http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4058.pdf Is this really the issue here? What I'm trying to do is not the same as what's discussed in the proposal, as the reading/writing of the unique_ptr doesn't have to be an atomic operation in my case. I just want to push a unique_ptr onto the queue, and spsc_queue can store all kinds of objects, which are not atomic either. It only uses atomic operations to keep track of the write and read indices, and those parts of the code don't need to be modified to make this work. As far as I see, the main problem storing unique_ptr's (or any other non-copyable but moveable object), is that the code relies on a copy constructor to store objects in its internal buffer. I added an overload using a move constructor and that seems to work (though I'm quite new to multi-threading or lockfree programming, so I could be missing some potential issues). Thomas

2 1

[Asio] null_buffers problem
by lin li 24 Nov '14

24 Nov '14

Hi, guys. I have some problem with null_buffers in Asio. According to the document, 'A null_buffers operation doesn't return until the I/O object is "ready" to perform the operation'. However, when I tried to use it in a asynchronous read, it keeps returning after all data has been received and the other end has closed the socket! So here is my questions: 1. what is "ready" exactly? 2. If we use null_buffers with async_read_some, will it detect some errors like disconnection and pass the error code to the completion handler?

2 1

[serialization] Customizing serialization of boost::variant
by Elizabeta 22 Nov '14

22 Nov '14

Hi When serialization boost::variant, in the xml archive 'which' element is included that specify the number of the type that appears in the boost::variant at compile time. I need to include in the archive also the name of the type for debugging purpose . Anyone have idea how to do that -- View this message in context: http://boost.2283326.n4.nabble.com/serialization-Customizing-serialization-… Sent from the Boost - Users mailing list archive at Nabble.com.

1 0

NT² 3.0 and Boost.SIMD - Stable release
by Joel Falcou 21 Nov '14

21 Nov '14

The first stable release of the 3.x series of MetaScale’s open-source software is available: NT² 3.0. It also includes its spin-off project, Boost.SIMD (not yet a Boost library). Many Issues have been closed since last beta. The main focus of this release cycle was to fix performances issues and to stabilize some parts of the API. Next step will be to separate NT2 and Boost.SIMD into separate repositories, thus making one more step toward Boost.SIMD submission into review. [ http://www.metascale.org/nt%C2%B2-3-0-and-boost-simd ] *Changes & Bug Fixes:* - Major performance improvements in both libraries - Added experimental support for the HPX runtime for parallelization on shared memory systems - Optimizations of many elemental functions, in particuler log/ex, frexp/ldexp and cbrt - More advanced shuffle pattern recognition for SIMD - Fixed issues with Visual Studio 2013 - More functions are force-inlined to ensure good performance - New functions for conversion between types and mixing of vectors of different sizes - Demo applications usable as benchmarks - Better handling of errors when an unsupported function is called - New API for custom memory allocators Full changelog is available at https://github.com/MetaScale/nt2/releases/tag/3.0.0. *How to get it ?* - Source and binary packages can be downloaded here: http://nt2.metascale.org/downloads - The release is also available on Github : https://github.com/MetaScale/nt2/releases - The main master branch is still under development : https://github.com/MetaScale/nt2

4 4

Thread prioritization
by Alexander Carôt 20 Nov '14

20 Nov '14

Hello all, is it correct that boost does not offer thread prioritization ? I am dealing with an application with a number of threads, which all depend on the realtime-scheduled sound card callback thread. These threads must have the same realtime scheduling priority. Is there a way to achieve this ? Thanks in advance, best Alex >

3 3

[BGL] [push_relabel_max_flow] multigraphs ?
by Pablo Madoery 20 Nov '14

20 Nov '14

I was wondering if the push_relabel_max_flow algorithm can be used in multigraphs. I mean, can I have two vertices joined by two edges: one in a direction an the other in the opposite direction with equal capacities ( 1000 for example ). It is clear in the documentation that the reverse edge must exist for each edge in the graph, so there must be 4 edges in the case I am describing. but the question is: does the algorithm works properly for this case ?

1 0

[BGL] [push_relabel_max_flow]
by Pablo Madoery 19 Nov '14

19 Nov '14

Hello, I am having trouble using the push_relabel_max_flow algorithm when i put std::numeric_limits<double>::max() as capacity attribute in some edges. is there a maximum value that I can use as capacities. which ?. This is the example I am using : #include <iostream> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/push_relabel_max_flow.hpp> #include <boost/graph/graphviz.hpp> using namespace std; using namespace boost; struct vertexInfo { }; struct edgeInfo { double capacity; double residualCapacity; double flow; adjacency_list_traits<vecS, vecS, bidirectionalS>::edge_descriptor rev; edgeInfo() { residualCapacity = 1000; } }; typedef adjacency_list<vecS, vecS, bidirectionalS, vertexInfo, edgeInfo> Graph; typedef Graph::edge_descriptor edge_d; const char* names[] = { "SV", "L1", "L2", "L3", "L4", "ET"}; template<typename Vertex> void create_edge(Graph& g, Vertex v0, Vertex v1, double capacity) { //the algorithm requires that for each edge u-v in the graph, the edge v-u also exists Graph::edge_descriptor ep0 = (add_edge(v0, v1, g)).first; Graph::edge_descriptor ep1 = (add_edge(v1, v0, g)).first; g[ep0].capacity = capacity; g[ep0].rev = ep1; g[ep1].capacity = 0; // the capacity of v-u needs to be 0 g[ep1].rev = ep0; } int main() { Graph graph; Graph::vertex_descriptor SV = add_vertex(graph); Graph::vertex_descriptor L1 = add_vertex(graph); Graph::vertex_descriptor L2 = add_vertex(graph); Graph::vertex_descriptor L3 = add_vertex(graph); Graph::vertex_descriptor L4 = add_vertex(graph); Graph::vertex_descriptor ET = add_vertex(graph); create_edge(graph, SV, L1, std::numeric_limits<double>::max()); create_edge(graph, SV, L2, std::numeric_limits<double>::max()); create_edge(graph, SV, L3, std::numeric_limits<double>::max()); create_edge(graph, SV, L4, std::numeric_limits<double>::max()); create_edge(graph, L3, ET, 1000); create_edge(graph, L4, L3, 1000); create_edge(graph, L2, L3, 1000); create_edge(graph, L1, L2, 1000); // arcos de vuelta create_edge(graph, L3, L4, 1000); create_edge(graph, L3, L2, 1000); create_edge(graph, L2, L1, 1000); std::cout << "Max flow: " << push_relabel_max_flow(graph, SV, ET, get(&edgeInfo::capacity, graph), get(&edgeInfo::residualCapacity, graph), get(&edgeInfo::rev, graph), get(boost::vertex_index, graph)) << std::endl; graph_traits<Graph>::vertex_iterator vi, vi_end; graph_traits<Graph>::out_edge_iterator ei, ei_end; cout.precision(20); for (tie(vi, vi_end) = vertices(graph); vi!= vi_end; ++vi) { for (tie(ei, ei_end) = out_edges(*vi, graph); ei != ei_end; ++ei) { graph[*ei].flow = graph[*ei].capacity - graph[*ei].residualCapacity; if (graph[*ei].capacity > 0) { std::cout << names[*vi] << " " << names[target(*ei, graph)] << " " << (graph[*ei].capacity - graph[*ei].residualCapacity) << "/" << graph[*ei].capacity << std::endl; } } } cout<<"end"<<endl; return 0; } ----------------------------------------------------------------------------------------------------------------------------- And this is the exception: /home/madoery/boost_1_55_0/boost/graph/push_relabel_max_flow.hpp:706: typename boost::property_traits<CapacityEdgeMap>::value_type boost::push_relabel_max_flow(Graph&, typename boost::graph_traits<Graph>::vertex_descriptor, typename boost::graph_traits<Graph>::vertex_descriptor, CapacityEdgeMap, ResidualCapacityEdgeMap, ReverseEdgeMap, VertexIndexMap) [with Graph = boost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS, vertexInfo, edgeInfo>, CapacityEdgeMap = boost::adj_list_edge_property_map<boost::bidirectional_tag, double, double&, long unsigned int, edgeInfo, double edgeInfo::*>, ResidualCapacityEdgeMap = boost::adj_list_edge_property_map<boost::bidirectional_tag, double, double&, long unsigned int, edgeInfo, double edgeInfo::*>, ReverseEdgeMap = boost::adj_list_edge_property_map<boost::bidirectional_tag, boost::detail::edge_desc_impl<boost::bidirectional_tag, long unsigned int>, boost::detail::edge_desc_impl<boost::bidirectional_tag, long unsigned int>&, long unsigned int, edgeInfo, boost::detail::edge_desc_impl<boost::bidirectional_tag, long unsigned int> edgeInfo::*>, VertexIndexMap = boost::vec_adj_list_vertex_id_map<vertexInfo, long unsigned int>, typename boost::property_traits<CapacityEdgeMap>::value_type = double, typename boost::graph_traits<Graph>::vertex_descriptor = long unsigned int]: Assertion `algo.is_flow()' failed. Thank You

2 2

More than strange performance test results of Boost.MultiIndex
by Ernest Zaslavsky 19 Nov '14

19 Nov '14

I was rewriting our production code since there were performance concerns and switched from our monstrous std::map to boost multi_index_containers which looked exactly what we need. Then when running performance tests I've noticed that once I use composite_key which includes string the performance drops in orders of magnitude, to be precise, 5 orders. Which, I would say, not reasonable at all. So I created a minimal repro case to post here and ran it on Coliru. Surprise! This behavior does not reproduce on GCC, moreover, the composite key with string for some reason was searched twice faster than int only composite. To me it sounds like a bug or in Boost.MultiIndex MS specific implementation (if such exists) or in MSVC. Tech details: VS2012, Win7x64. The code was compiled and linked targeting x64 architecture. Test output on my local machine: Populating data. Index size: 999999 Running FlyweightMICTest::deepTest Checking getTestData perf. 999999 sum of all IDs. 1M calls took 0 seconds or 125ns per call. ------------------------------------------------------------- Populating data. Index size: 999999 Running FlyweightMICTestWithString::deepTest Checking getTestData perf. 99 sum of all IDs. 99 calls took 1 seconds or 10132326ns per call. =============================================================== Coliru output (live example can be found here http://coliru.stacked-crooked.com/a/ef76d297279f15a8) Populating data. Index size: 999999 Running deepTest Checking getTestData perf. 999999 sum of all IDs. 1M calls took 0 seconds or 395ns per call. ------------------------------------------------------------- Populating data. Index size: 999999 Running deepTest Checking getTestData perf. 999999 sum of all IDs. 999999 calls took 0 seconds or 181ns per call. =============================================================== [Read More]<http://feeds.feedburner.com/~r/sizmek-blog/~6/1> [http://www.sizmek.com/Sizmek.png]<http://www.sizmek.com/>

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Re: [Boost-users] Boost-users Digest, Vol 3971, Issue 2
by vibhor aggarwal 18 Nov '14

18 Nov '14

Thanks for the message Joaquin! I am running the boost invariant checks for multi-index and something which took a minute is now taking a full day to run. Any how, I haven't had any of the assertions fail in 5 iterations which completed so far and I have moved to version 1.57.0 Will get back if I see any issues with this again. On Thursday, 13 November 2014 10:30 PM, "boost-users-request(a)lists.boost.org" <boost-users-request(a)lists.boost.org> wrote: Send Boost-users mailing list submissions to boost-users(a)lists.boost.org To subscribe or unsubscribe via the World Wide Web, visit http://lists.boost.org/mailman/listinfo.cgi/boost-users or, via email, send a message with subject or body 'help' to boost-users-request(a)lists.boost.org You can reach the person managing the list at boost-users-owner(a)lists.boost.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Boost-users digest..." Today's Topics: 1. Re: [Mutli-Index, InterProcess] Multi-index stability issue with interprocess? (Joaquin M Lopez Munoz) 2. [Graph] A* with heterogeneous heuristics (Sensei) 3. 1.57.0 link errors (missing ctor/dtor for boost::archive::detail::shared_ptr_helper) (David Abdurachmanov) 4. [BGL] Shortest-Path subject to length constraint (Yun Liu) ---------------------------------------------------------------------- Message: 1 Date: Thu, 13 Nov 2014 10:41:08 +0000 (UTC) From: Joaquin M Lopez Munoz <joaquin(a)tid.es> To: boost-users(a)lists.boost.org Subject: Re: [Boost-users] [Mutli-Index, InterProcess] Multi-index stability issue with interprocess? Message-ID: <loom.20141113T111909-42(a)post.gmane.org> Content-Type: text/plain; charset=utf-8 vibhor aggarwal <vibhor.aggarwal <at> yahoo.com> writes: > > I am creating a multi-index [...] and storing that in a managed > memory mapped file (boos::interprocess) [...] > All the data is first inserted into the multi-index once and then it > is read from the muti-index with a query [...] > > boost::tie(l, u) = m_p_mi_ts->get<0>(). > equal_range(boost::make_tuple(i, j)); > > We are testing this whole process over and over again (each iteration > is a new run of the process), and once in every 50 or so iterations > we get a segment fault inside boost on firing the query. Here is the > boost part of the stack from the core dump: With so little information, I can only guess: the crash is hapenning at a very superficial level into equal_range, namely when dereferencing the container's header node (the top of the rb-tree ordered indices are based on). This suggests that the container layout is seriously screwed; possible reasons: * Memory overwrites from some adjacent structure * File corruption (?) * m_p_mi has been changed somewhere * Some sort of overrun within the memory-mapped file It'd be best if you could provide a testing case for this or some more context. If this is not an option, you can activate Boost.MultiIndex invariant-checking mode: http://www.boost.org/libs/multi_index/doc/tutorial /debug.html#invariant_check which will assert as soon as some internal corruption is detected (caveat: this mode will reduce performance drastically). Joaqu?n M L?pez Mu?oz Telef?nica ------------------------------ Message: 2 Date: Thu, 13 Nov 2014 12:41:32 +0100 From: Sensei <senseiwa(a)gmail.com> To: boost-users(a)lists.boost.org Subject: [Boost-users] [Graph] A* with heterogeneous heuristics Message-ID: <546498EC.6070204(a)gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Dear all, I haven't given up in trying to implement an A* algorithm with BGL. My problem is theoretically simple, as in some previous posts. Given a graph of letters, and a word, find the path in the graph that minimizes the distance between the letters of the word and the nodes in the graph. It's best to show an example: /* * B H * / \ / * A---D---F---G---I * \ /\ * C E * * input: A E I O U * result: A D F G I */ With that graph, my heuristic should take into account not just the letter in the graph per se, but the *corresponding* one in the input word. So, starting with "AEIOU" the search will: - expand A (A in **A**EIOU) - find B, C, D - expand D (closest to E in A**E**IOU) - find D, F - expand F (closest to I in AE**I**OU) - find G - expand G (only one, closest to O in AEI**O**U) - find H, I - expand U (closest to U in AEIO**U**) This settings could also be more complicated, adding weights to edges, but for now I am happy with this problem. What I've done now? Implementing my own A* algorithm, by hand. Of course this might work, but I'd prefer using BGL's facilities. I must say that I am quite confused about BGL's data structures, as for instance in the A* cities example (1), we need to create a weight map, so what if I don't need weights? Moreover, predecessors and distances are instantiated with a std::vector, but what happens if I need to operate on a very large graph, for instance 200M nodes? Moreover, what will happen when I will distribute the graph over a cluster with Boost Parallel Graph? ... Ok maybe this is too ahead of the time! :) Basically, I'd need to replicate my A* ugly by-hand implementation with custom visitors and custom heuristics. Below you may find my failed attempt. I need some help with this, because I find the documentation a little bit hard to understand, especially when some newbie like me approaches Boost :) Failures in my code: I can't get to define a non-weighted graph, and the call to the A* search is cryptic: I don't have weights. Should I define fake ones for instance all equal to 1? I really hope you guys can help me in this, my code works, but using BGL would be best! Thanks! (1) http://www.boost.org/doc/libs/1_57_0/libs/graph/example/astar-cities.cpp #include <iostream> #include <unordered_map> #include <vector> #include <string> #include <utility> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/breadth_first_search.hpp> #include <boost/graph/depth_first_search.hpp> #include <boost/graph/astar_search.hpp> typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS > graph; typedef boost::graph_traits<graph>::edge_iterator edge_iterator; // Custom A* heuristic template <class Graph, class CostType> class bestmatch_heuristic : public boost::astar_heuristic<Graph, CostType> { public: typedef typename boost::graph_traits<Graph>::vertex_descriptor Vertex; bestmatch_heuristic() { }; CostType operator()(Vertex u) { std::cout << ">>>> h(" << u << ") = " << 1 << std::endl; return 1; } private: }; // Used to end the A* search algorithm struct end_astar { }; // Custom A* visitor template <class Vertex> class bestmatch_visitor : public boost::default_astar_visitor { public: bestmatch_visitor(Vertex goal) : destination_(goal) { }; template<class Graph> void discover_vertex(Vertex u, const Graph &g) { std::cout << "discover " << u << std::endl; } template <class Graph> void examine_vertex(Vertex u, Graph& g) { std::cout << "examine " << u << std::endl; if (u == destination_) throw end_astar(); } private: Vertex destination_; }; int main() { /* * B H * / \ / * A---D---F---G---I * \ /\ * C E * * input: A E I O U * result: A D F G I */ std::unordered_map<char, std::size_t> letters; auto getletter = [](std::size_t i) -> char { return 'A' + i; }; for (int i = 'A'; i <= 'I'; i++) letters[i] = i - 'A'; graph g; boost::add_edge(letters['A'], letters['B'], g); boost::add_edge(letters['A'], letters['C'], g); boost::add_edge(letters['A'], letters['D'], g); boost::add_edge(letters['B'], letters['D'], g); boost::add_edge(letters['C'], letters['D'], g); boost::add_edge(letters['D'], letters['E'], g); boost::add_edge(letters['D'], letters['F'], g); boost::add_edge(letters['F'], letters['G'], g); boost::add_edge(letters['G'], letters['H'], g); boost::add_edge(letters['G'], letters['I'], g); edge_iterator ei, ee; for (boost::tie(ei, ee) = boost::edges(g); ei != ee; ei++) { std::cout << getletter(boost::source(*ei, g)) << " -> " << getletter(boost::target(*ei, g)) << std::endl; } // Heuristics bestmatch_heuristic<graph, int> h; // Predecessors std::vector<graph::vertex_descriptor> p(boost::num_vertices(g)); try { #if 0 boost::astar_search_tree(// Graph g, // Start node letters['A'], // Heuristics bestmatch_heuristic<graph, int>(), // Predecessor map boost::predecessor_map(boost::make_iterator_property_map(p.begin(), boost::get(boost::vertex_index, g)))); #endif } catch (end_astar e) { } } ------------------------------ Message: 3 Date: Thu, 13 Nov 2014 10:07:07 +0100 From: David Abdurachmanov <david.abdurachmanov(a)gmail.com> To: boost-users(a)lists.boost.org Cc: amey(a)rrsd.com Subject: [Boost-users] 1.57.0 link errors (missing ctor/dtor for boost::archive::detail::shared_ptr_helper) Message-ID: <C512A56C-8078-438E-BDBC-376A9EF590F9(a)gmail.com> Content-Type: text/plain; charset="us-ascii" Hi, I am moving to Boost 1.57.0 and having issues with some code related to serialization. https://github.com/cms-sw/cmssw/blob/CMSSW_7_3_X/CondFormats/Serialization/… https://github.com/cms-sw/cmssw/blob/CMSSW_7_3_X/CondFormats/Serialization/… In both cases the problem is here: #if BOOST_VERSION >= 103500 #include <boost/archive/shared_ptr_helper.hpp> #endif [snip] #if BOOST_VERSION >= 103500 // mix-in helper class for serializing shared_ptr , public boost::archive::detail::shared_ptr_helper #endif A similar (or the same) problem is reported here: http://boost.2283326.n4.nabble.com/Serialization-link-error-in-1-56-td46668… It seems that ctor/dtor are not exported anymore: /testSerializationDQMObjects.o: In function `eos::portable_oarchive::portable_oarchive(std::ostream& , unsigned int)': testSerializationDQMObjects.cpp:(.text._ZN3eos17portable_oarchiveC2ERSoj[_ZN3eos17portable_oarchiveC5ERSoj]+0x54): undefined reference to `boost::archive::detail::shared_ptr_helper: :shared_ptr_helper()' testSerializationDQMObjects.cpp:(.text._ZN3eos17portable_oarchiveC2ERSoj[_ZN3eos17portable_oarchiveC5ERSoj]+0x1c1): undefined reference to `boost::archive::detail::shared_ptr_helper ::~shared_ptr_helper()' boost::serialization::shared_ptr_helper does not seem to be a drop-in replacement at first look. There is also 'shared_ptr_helper_base', but is only available in the implementation file. Is such mix-in class still available in a new Boost version? Thanks, david

1 0

Iostreams: how can I control my (ostream) filter?
by Akim Demaille 16 Nov '14

16 Nov '14

Hi! I'm trying to use Boost.Iostream to create a filter that will escape some characters (typically backslash must be backslashed). This is to conform with the syntax of an output format that requires some portions to be escaped this way. But other place must be left untouched. My problem is I don't find a means to "talk" to my filter. My first attempt used two streams: the "real" ostream and the filtered one that wraps it. Of course it failed: both streams are not synchronized, and buffers are flushed at different moments resulting in scrambled output. I don't want to flush too often (I got to keep my throughput high), so that's ruled out. My second attempt was to introduce an xalloc-based custom iomanip to enable/disable the processing in my filter. But my problem is that in my filter, I don't know how to reach the final ostream and fetch it pword, so I failed to have it work. From the syntax point of view (from the caller viewpoint) that was my favorite approach. In my third attempt, I have to boolean variable living in the caller frame, taken as a bool& by my filter's actor, and checked in its "write" function to decide whether to escape or not. This looks worrying (bool& members don't look nice), and anyway does not work nicely, again, with buffers: the asynchrony between setting/unsetting the boolean and using it breaks everything. So, what are the good options? I think I really needed something like an iomanipulator which ensures that "sequentiality" is preserved, but how should I do that? Thanks in advance! PS/ One not-good-option would be to have my filter try to "parse" what it is outputting to decide what's the current state, and whether it should escape or not. First, things become uselessly complex, and second, anyway that's not right; for instance when I'm in a string, double-quotes should be escaped, or mark the end of the string. The filter cannot know which kind of double-quote it just saw, but I know, so _I_ should change the state at that time, not it.

2 4

Why does `boost::asio::deadline_timer` allocate a `timer_queue` instance for each `deadline_timer` object?
by Wang Danqi 16 Nov '14

16 Nov '14

Hi I am looking into the implementation of `boost::asio::deadline_timer`, based on boost 1.52. As described in [the article on highscore](http://en.highscore.de/cpp/boost/asio.html#asio_extensions), it is implemented in three parts: * `deadline_timer`, the i/o object * `deadline_timer_service`, the service * `detail::deadline_timer_service`, the service implementation There will be a single instance of `deadline_timer_service` serving many `deadline_timer` objects. An instance of `detail::deadline_timer_service` is created for each `deadline_timer` object. Moreover, the timers are scheduled by a scheduler, which is usually a reactor (i.e. `epoll_reactor` on Linux in most cases). There is a `timer_queue_` member of type `timer_queue` in `detail::deadline_timer_service` which is a heap that stores scheduled timers. This means that there will be one instance of `timer_queue` for each `deadline_timer` object. Multiple `timer_queue` objects can be added to the scheduler by `add_timer_queue()`, and they are managed by a class `timer_queue_set`. My question is, why `asio` create multiple queues to handle timers? What is the drawback if we have a single timer queue instance in the scheduler that all timers can share? Please note that I am asking about the `boost::asio::deadline_timer`, not the example in the highscore link. I have posted this question on stackoverflow previously [here](http://stackoverflow.com/q/26922754/930095) -- Best wishes, Wang Danqi

2 2

Re: [Boost-users] lockfree::spsc_queue & move semantics
by quang.trinh＠gmail.com 15 Nov '14

15 Nov '14

------Original Message------ From: Bjorn Reese Sender: Boost-users To: boost-users(a)lists.boost.org ReplyTo: boost-users(a)lists.boost.org Subject: Re: [Boost-users] lockfree::spsc_queue & move semantics Sent: Nov 10, 2014 2:39 PM On 11/09/2014 09:49 PM, Thomas Danckaert wrote: > I'd like to use a spsc_queue of unique_ptr's to bigger objects, to > transfer ownership between threads. That way, I can create/allocate an This limitation inherited from atomic, and I am afraid that it is a bit more complicated than adding a move constructor. Fortunately, there is a C++ proposal to address the problem: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4058.pdf _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users Sent from my BlackBerry device on the Rogers Wireless Network

1 0

How to track boost::asio pending handlers
by Thierry Morigault 14 Nov '14

14 Nov '14

Hi, I am debugging a huge application with numbers of handlers posted in a boost::asio::io_service, running on Windows 7, Visual Studio 2012 and with boost 1.55. My problem is that the io_service doesn't stop because of pending handlers ... And i can't know what are precisely these handlers : there is only a function in boost::io_service which give the number of pending handlers. Is there a way to display the name of the different pending handlers in the io_service ? It can be so helpful ! I know the macro BOOST_ASIO_ENABLE_HANDLER_TRACKING but this only prints the boost::asio internal functions names (async_accept, async write etc.), and not my proper posted handlers.

1 0

[BGL] Shortest-Path subject to length constraint
by Yun Liu 13 Nov '14

13 Nov '14

Hi all, apologies in advance if this question is trivial; I couldn't find anything like it asked previously in the mailing list. My question is, if I have a directed graph (with non-negative edge weights, to keep things simple for now), I would like to find the shortest-cost path from a source node to target node, but with the constraint on the maximum number of edges allowed. For example, if I have the graph with vertices {A,B,C,D} and edges: A->B (cost 1), B->C (cost 1), C->D (cost 1), A->D (cost 1000), but I have the constraint that my path should only be a maximum of 2 edges, the correct solution would still be A->D with cost 1000. Looking through the previous BGL examples, say with bellman-ford or Dijkstra, it did not seem immediately obvious how to enforce this stipulation. Thanks again for any ideas! -Yun

1 0

[Graph] A* with heterogeneous heuristics
by Sensei 13 Nov '14

13 Nov '14

Dear all, I haven't given up in trying to implement an A* algorithm with BGL. My problem is theoretically simple, as in some previous posts. Given a graph of letters, and a word, find the path in the graph that minimizes the distance between the letters of the word and the nodes in the graph. It's best to show an example: /* * B H * / \ / * A---D---F---G---I * \ /\ * C E * * input: A E I O U * result: A D F G I */ With that graph, my heuristic should take into account not just the letter in the graph per se, but the *corresponding* one in the input word. So, starting with "AEIOU" the search will: - expand A (A in **A**EIOU) - find B, C, D - expand D (closest to E in A**E**IOU) - find D, F - expand F (closest to I in AE**I**OU) - find G - expand G (only one, closest to O in AEI**O**U) - find H, I - expand U (closest to U in AEIO**U**) This settings could also be more complicated, adding weights to edges, but for now I am happy with this problem. What I've done now? Implementing my own A* algorithm, by hand. Of course this might work, but I'd prefer using BGL's facilities. I must say that I am quite confused about BGL's data structures, as for instance in the A* cities example (1), we need to create a weight map, so what if I don't need weights? Moreover, predecessors and distances are instantiated with a std::vector, but what happens if I need to operate on a very large graph, for instance 200M nodes? Moreover, what will happen when I will distribute the graph over a cluster with Boost Parallel Graph? ... Ok maybe this is too ahead of the time! :) Basically, I'd need to replicate my A* ugly by-hand implementation with custom visitors and custom heuristics. Below you may find my failed attempt. I need some help with this, because I find the documentation a little bit hard to understand, especially when some newbie like me approaches Boost :) Failures in my code: I can't get to define a non-weighted graph, and the call to the A* search is cryptic: I don't have weights. Should I define fake ones for instance all equal to 1? I really hope you guys can help me in this, my code works, but using BGL would be best! Thanks! (1) http://www.boost.org/doc/libs/1_57_0/libs/graph/example/astar-cities.cpp #include <iostream> #include <unordered_map> #include <vector> #include <string> #include <utility> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/breadth_first_search.hpp> #include <boost/graph/depth_first_search.hpp> #include <boost/graph/astar_search.hpp> typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS > graph; typedef boost::graph_traits<graph>::edge_iterator edge_iterator; // Custom A* heuristic template <class Graph, class CostType> class bestmatch_heuristic : public boost::astar_heuristic<Graph, CostType> { public: typedef typename boost::graph_traits<Graph>::vertex_descriptor Vertex; bestmatch_heuristic() { }; CostType operator()(Vertex u) { std::cout << ">>>> h(" << u << ") = " << 1 << std::endl; return 1; } private: }; // Used to end the A* search algorithm struct end_astar { }; // Custom A* visitor template <class Vertex> class bestmatch_visitor : public boost::default_astar_visitor { public: bestmatch_visitor(Vertex goal) : destination_(goal) { }; template<class Graph> void discover_vertex(Vertex u, const Graph &g) { std::cout << "discover " << u << std::endl; } template <class Graph> void examine_vertex(Vertex u, Graph& g) { std::cout << "examine " << u << std::endl; if (u == destination_) throw end_astar(); } private: Vertex destination_; }; int main() { /* * B H * / \ / * A---D---F---G---I * \ /\ * C E * * input: A E I O U * result: A D F G I */ std::unordered_map<char, std::size_t> letters; auto getletter = [](std::size_t i) -> char { return 'A' + i; }; for (int i = 'A'; i <= 'I'; i++) letters[i] = i - 'A'; graph g; boost::add_edge(letters['A'], letters['B'], g); boost::add_edge(letters['A'], letters['C'], g); boost::add_edge(letters['A'], letters['D'], g); boost::add_edge(letters['B'], letters['D'], g); boost::add_edge(letters['C'], letters['D'], g); boost::add_edge(letters['D'], letters['E'], g); boost::add_edge(letters['D'], letters['F'], g); boost::add_edge(letters['F'], letters['G'], g); boost::add_edge(letters['G'], letters['H'], g); boost::add_edge(letters['G'], letters['I'], g); edge_iterator ei, ee; for (boost::tie(ei, ee) = boost::edges(g); ei != ee; ei++) { std::cout << getletter(boost::source(*ei, g)) << " -> " << getletter(boost::target(*ei, g)) << std::endl; } // Heuristics bestmatch_heuristic<graph, int> h; // Predecessors std::vector<graph::vertex_descriptor> p(boost::num_vertices(g)); try { #if 0 boost::astar_search_tree(// Graph g, // Start node letters['A'], // Heuristics bestmatch_heuristic<graph, int>(), // Predecessor map boost::predecessor_map(boost::make_iterator_property_map(p.begin(), boost::get(boost::vertex_index, g)))); #endif } catch (end_astar e) { } }

1 0

[Mutli-Index, InterProcess] Multi-index stability issue with interprocess?
by vibhor aggarwal 13 Nov '14

13 Nov '14

I am creating a multi-index on three members of a class (two int32_t and one std::pair<int32_t, int32_t> and storing that in a managed memory mapped file (boos::interprocess). I am using GCC 4.8.2 for compilation and boost version 1.56.beta1All the data is first inserted into the multi-index once and then it is read from the muti-index with a query on the first two int32_t values (There is no concurrency and insertion and query is being done within the same process). The mutliindex is defined as: typedef bmi::multi_index_container < Trace, bmi::indexed_by < bmi::ordered_non_unique < bmi::composite_key < Trace, BOOST_MULTI_INDEX_MEMBER(Trace, int32_t, m_x), BOOST_MULTI_INDEX_MEMBER(Trace, int32_t, m_y), BOOST_MULTI_INDEX_MEMBER(Trace, int_pair_t, m_volume) > > > , managed_mapped_file::allocator<Trace>::type > trace_set_t; The query is: boost::tie(l, u) = m_p_mi_ts->get<0>().equal_range(boost::make_tuple(i, j)); We are testing this whole process over and over again (each iteration is a new run of the process), and once in every 50 or so iterations we get a segment fault inside boost on firing the query. Here is the boost part of the stack from the core dump: #0 0x00002b748b6ac0ec in boost::interprocess::offset_ptr<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::index_node_base<Seismic::Data::Trace, boost::interprocess::allocator<Seismic::Data::Trace, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0ul>, 0ul>, boost::interprocess::iset_index> > > >, long, unsigned long, 0ul>::get() const () at /glb/data/ifshou_cdis05/projects/cdis/installed/boost/1.56.0.beta1/usr/local/include/boost/interprocess/offset_ptr.hpp:346#1 0x00002b748b6a8934 in boost::interprocess::offset_ptr<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::index_node_base<Seismic::Data::Trace, boost::interprocess::allocator<Seismic::Data::Trace, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0ul>, 0ul>, boost::interprocess::iset_index> > > >, long, unsigned long, 0ul>::operator*() const () at /glb/data/ifshou_cdis05/projects/cdis/installed/boost/1.56.0.beta1/usr/local/include/boost/interprocess/offset_ptr.hpp:360#2 0x00002b748b6a5932 in boost::multi_index::multi_index_container<Seismic::Data::Trace, boost::multi_index::indexed_by<boost::multi_index::ordered_non_unique<boost::multi_index::composite_key<Seismic::Data::Trace, boost::multi_index::member<Seismic::Data::Trace, int, &(Seismic::Data::Trace::m_x)>, boost::multi_index::member<Seismic::Data::Trace, int, &(Seismic::Data::Trace::m_y)>, boost::multi_index::member<Seismic::Data::Trace, std::pair<int, int>, &(Seismic::Data::Trace::m_volume)>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>, mpl_::na, mpl_::na>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::interprocess::allocator<Seismic::Data::Trace, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0ul>, 0ul>, boost::interprocess::iset_index> > >::header() const () at /glb/data/ifshou_cdis05/projects/cdis/installed/boost/1.56.0.beta1/usr/local/include/boost/multi_index_container.hpp:525#3 0x00002b748b6a3250 in boost::multi_index::detail::index_base<Seismic::Data::Trace, boost::multi_index::indexed_by<boost::multi_index::ordered_non_unique<boost::multi_index::composite_key<Seismic::Data::Trace, boost::multi_index::member<Seismic::Data::Trace, int, &(Seismic::Data::Trace::m_x)>, boost::multi_index::member<Seismic::Data::Trace, int, &(Seismic::Data::Trace::m_y)>, boost::multi_index::member<Seismic::Data::Trace, std::pair<int, int>, &(Seismic::Data::Trace::m_volume)>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>, mpl_::na, mpl_::na>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::interprocess::allocator<Seismic::Data::Trace, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0ul>, 0ul>, boost::interprocess::iset_index> > >::final_header() const () at /glb/data/ifshou_cdis05/projects/cdis/installed/boost/1.56.0.beta1/usr/local/include/boost/multi_index/detail/index_base.hpp:212#4 0x00002b748b6a022c in boost::multi_index::detail::ordered_index<boost::multi_index::composite_key<Seismic::Data::Trace, boost::multi_index::member<Seismic::Data::Trace, int, &(Seismic::Data::Trace::m_x)>, boost::multi_index::member<Seismic::Data::Trace, int, &(Seismic::Data::Trace::m_y)>, boost::multi_index::member<Seismic::Data::Trace, std::pair<int, int>, &(Seismic::Data::Trace::m_volume)>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>, std::less<boost::multi_index::composite_key_result<boost::multi_index::composite_key<Seismic::Data::Trace, boost::multi_index::member<Seismic::Data::Trace, int, &(Seismic::Data::Trace::m_x)>, boost::multi_index::member<Seismic::Data::Trace, int, &(Seismic::Data::Trace::m_y)>, boost::multi_index::member<Seismic::Data::Trace, std::pair<int, int>, &(Seismic::Data::Trace::m_volume)>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> > >, boost::multi_index::detail::nth_layer<1, Seismic::Data::Trace, boost::multi_index::indexed_by<boost::multi_index::ordered_non_unique<boost::multi_index::composite_key<Seismic::Data::Trace, boost::multi_index::member<Seismic::Data::Trace, int, &(Seismic::Data::Trace::m_x)>, boost::multi_index::member<Seismic::Data::Trace, int, &(Seismic::Data::Trace::m_y)>, boost::multi_index::member<Seismic::Data::Trace, std::pair<int, int>, &(Seismic::Data::Trace::m_volume)>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>, mpl_::na, mpl_::na>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::interprocess::allocator<Seismic::Data::Trace, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0ul>, 0ul>, boost::interprocess::iset_index> > >, boost::mpl::vector0<mpl_::na>, boost::multi_index::detail::ordered_non_unique_tag>::header() const () at /glb/data/ifshou_cdis05/projects/cdis/installed/boost/1.56.0.beta1/usr/local/include/boost/multi_index/ordered_index.hpp:973#5 0x00002b748b69cbed in std::pair<boost::multi_index::detail::bidir_node_iterator<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::index_node_base<Seismic::Data::Trace, boost::interprocess::allocator<Seismic::Data::Trace, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0ul>, 0ul>, boost::interprocess::iset_index> > > > >, boost::multi_index::detail::bidir_node_iterator<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::index_node_base<Seismic::Data::Trace, boost::interprocess::allocator<Seismic::Data::Trace, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0ul>, 0ul>, boost::interprocess::iset_index> > > > > > boost::multi_index::detail::ordered_index<boost::multi_index::composite_key<Seismic::Data::Trace, boost::multi_index::member<Seismic::Data::Trace, int, &(Seismic::Data::Trace::m_x)>, boost::multi_index::member<Seismic::Data::Trace, int, &(Seismic::Data::Trace::m_y)>, boost::multi_index::member<Seismic::Data::Trace, std::pair<int, int>, &(Seismic::Data::Trace::m_volume)>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>, std::less<boost::multi_index::composite_key_result<boost::multi_index::composite_key<Seismic::Data::Trace, boost::multi_index::member<Seismic::Data::Trace, int, &(Seismic::Data::Trace::m_x)>, boost::multi_index::member<Seismic::Data::Trace, int, &(Seismic::Data::Trace::m_y)>, boost::multi_index::member<Seismic::Data::Trace, std::pair<int, int>, &(Seismic::Data::Trace::m_volume)>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> > >, boost::multi_index::detail::nth_layer<1, Seismic::Data::Trace, boost::multi_index::indexed_by<boost::multi_index::ordered_non_unique<boost::multi_index::composite_key<Seismic::Data::Trace, boost::multi_index::member<Seismic::Data::Trace, int, &(Seismic::Data::Trace::m_x)>, boost::multi_index::member<Seismic::Data::Trace, int, &(Seismic::Data::Trace::m_y)>, boost::multi_index::member<Seismic::Data::Trace, std::pair<int, int>, &(Seismic::Data::Trace::m_volume)>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>, mpl_::na, mpl_::na>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::interprocess::allocator<Seismic::Data::Trace, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0ul>, 0ul>, boost::interprocess::iset_index> > >, boost::mpl::vector0<mpl_::na>, boost::multi_index::detail::ordered_non_unique_tag>::equal_range<boost::tuples::tuple<int, int, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> >(boost::tuples::tuple<int, int, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> const&) const () at /glb/data/ifshou_cdis05/projects/cdis/installed/boost/1.56.0.beta1/usr/local/include/boost/multi_index/ordered_index.hpp:556 Any idea what might be happening? Thanks

2 1

1.57.0 link errors (missing ctor/dtor for boost::archive::detail::shared_ptr_helper)
by David Abdurachmanov 13 Nov '14

13 Nov '14

Hi, I am moving to Boost 1.57.0 and having issues with some code related to serialization. https://github.com/cms-sw/cmssw/blob/CMSSW_7_3_X/CondFormats/Serialization/… https://github.com/cms-sw/cmssw/blob/CMSSW_7_3_X/CondFormats/Serialization/… In both cases the problem is here: #if BOOST_VERSION >= 103500 #include <boost/archive/shared_ptr_helper.hpp> #endif [snip] #if BOOST_VERSION >= 103500 // mix-in helper class for serializing shared_ptr , public boost::archive::detail::shared_ptr_helper #endif A similar (or the same) problem is reported here: http://boost.2283326.n4.nabble.com/Serialization-link-error-in-1-56-td46668… It seems that ctor/dtor are not exported anymore: /testSerializationDQMObjects.o: In function `eos::portable_oarchive::portable_oarchive(std::ostream& , unsigned int)': testSerializationDQMObjects.cpp:(.text._ZN3eos17portable_oarchiveC2ERSoj[_ZN3eos17portable_oarchiveC5ERSoj]+0x54): undefined reference to `boost::archive::detail::shared_ptr_helper: :shared_ptr_helper()' testSerializationDQMObjects.cpp:(.text._ZN3eos17portable_oarchiveC2ERSoj[_ZN3eos17portable_oarchiveC5ERSoj]+0x1c1): undefined reference to `boost::archive::detail::shared_ptr_helper ::~shared_ptr_helper()' boost::serialization::shared_ptr_helper does not seem to be a drop-in replacement at first look. There is also 'shared_ptr_helper_base', but is only available in the implementation file. Is such mix-in class still available in a new Boost version? Thanks, david

1 0

[serialization] Treatment of corrupt archives - assert vs. exception throw
by Gabriel Redner 12 Nov '14

12 Nov '14

Hi folks, I'm dealing with binary archives which may have been corrupted enroute to my code. My naive expectation was that the serialization library should throw an exception when it encounters something in the input stream it doesn't understand (in which case my code can react gracefully). But, I've found that: 1. There exist cases where serialization will just assert and bring down the process 2. The documentation suggests that an exception should be thrown, but I didn't find any strong statement of this, so I am not sure whether it is a contract of the library. My first and most pressing question is: is it a guarantee of the library that invalid input should result in an exception and not an assert? If this is not so, I think it should be documented much more clearly. If it is so, then this message is a bug report. There's an assert in archive/basic_binary_iprimitive.hpp:98 that can be triggered if the bytes in the archive which represent a bool actually contain a value other than 0 or 1. One can trigger this in a test case like so (on x86_64 Linux, at least): ========== #include <boost/archive/binary_oarchive.hpp> #include <boost/archive/binary_iarchive.hpp> #include <fstream> int main() { { std::ofstream of("archive.bin", std::ios_base::binary); boost::archive::binary_oarchive oa(of); unsigned char i = 2; oa << i; } { std::ifstream f("archive.bin", std::ios_base::binary); boost::archive::binary_iarchive ia(f); bool b; // note different type than what was saved, but same size ia >> b; // assert! } } ========== Let me know if this is a bug that I should report to the tracker, or a feature. Thanks, -Gabe

3 3

BGL - shortest widest path
by Mark Fanara 12 Nov '14

12 Nov '14

I am trying to find the "shortest-widest path" between a single source and target node in an undirected graph (less than 25 nodes). (In my case, a shortest widest path is the maximum bandwidth path. If there are several such paths, it is the one with the least number of hops.) See W i k i p e d i a entry on "Widest path problem" I have successfully used dijkstra_shortest_paths() with a custom combine() function to find the maximum bandwidth path, however this does not take into account the possibility of more than one path with the same maximum bandwidth. In that case, I am looking for the one with the fewest hops. I am not clear on the meaning of some of the graph theory terms --- Is the problem I am trying to solve similar too, or the same as, a maximum flow problem? If so, as I am using an undirected graph, which boost algorithm should I use and how should I create a directed graph from my undirected graph? Would really appreciate an example, perhaps something that prints the resulting vertices in from-source-to-sink order.

1 0

[Test] failure linking tests dynamically
by Latimerius 11 Nov '14

11 Nov '14

Hello, I'm evaluating Boost.Test. I did the initial evaluation using the header-only variant and now I'd like to move to dynamic linking the Test library for a larger-scale deployment. However, all attempts so far failed due to Undefined symbols for architecture x86_64: "_main", referenced from: implicit entry/start for main executable ld: symbol(s) not found for architecture x86_64 I'd put it down to my lack of experience with Test, or Boost in general, however I noticed that my libs/test/example's don't seem to build either. I'm on OS X Yosemite. I compile Boost with ./bootstrap.sh --prefix=<my_dir> ./b2 cxxflags="-stdlib=libc++" linkflags="-stdlib=libc++" ./b2 install As this doesn't seem to compile the necessary .dylibs I added <define>BOOST_TEST_DYN_LINK=1 <link>shared to the "requirements" section of the first target in libs/test/build/Jamfile.v2 and rebuilt just Boost.Test. Although I don't actually know what I was doing, this did seem to build the Boost.Test dynamic libraries, which tests are however failing to link against. The result looks the same on 1_56_0 and 1_57_0. Could someone please help me find the problem? I'm dubious about my building procedure in particular, could someone give me a complete sequence of steps necessary to build Boost with Boost.Test ready to be linked dynamically? I check the documentation, which is good and detailed but deals with various aspects in isolation and doesn't give a newcomer a good idea of the overall process. Cheers!

2 4

boost.container.vector::operator==() bug?
by niXman 10 Nov '14

10 Nov '14

Hi, https://github.com/boostorg/container/blob/master/include/boost/container/v… Explained: if ( !(1 != 1) ) Another question is, why 'memcmp()' not used for vectors of fundamental types? -- Regards, niXman ___________________________________________________ Dual-target(32 & 64-bit) MinGW-W64 compilers for 32 and 64-bit Windows: http://sourceforge.net/projects/mingw-w64/ ___________________________________________________ Another online IDE: http://liveworkspace.org/

4 10

lockfree::spsc_queue & move semantics
by Thomas Danckaert 10 Nov '14

10 Nov '14

I'd like to use a spsc_queue of unique_ptr's to bigger objects, to transfer ownership between threads. That way, I can create/allocate an object in a non-realtime thread, then transfer ownership to a realtime thread using a lockfree queue, and, using another queue, pass on the unique_ptr to another thread that takes care of cleanup when the realtime thread no longer needs the it. For example: boost::lockfree::spsc_queue<unique_ptr<string>, boost::lockfree::capacity<10> > cb; Unfortunately, spsc_queue does not use move semantics (methods to push onto the queue take parameters as const reference and construct a copy in the queues internal storage), so i can not cb.push() a unique_ptr<string> onto my queue. Is it reasonable to want to add this, and if so, what would be the best place to submit a request? (I managed to get a simple example working by adding rvalue reference overrides of the queue's push() methods, and using std::move in the pop() method) bool push(T && t) { }; Also, I noticed that the destructor for the spsc_queue (with size fixed at compile-time) does not run destructors for it's contents. What could be the reason for this? Thomas

2 1

[scope_exit] 1.57 MSVC C4003 warning
by Filip Konvička 10 Nov '14

10 Nov '14

Hi, Any use of BOOST_SCOPE_EXIT in 1.57 seems to emit warning C4003 on MSVC 2012 and 2013: warning C4003: not enough actual parameters for macro 'BOOST_PP_EXPAND_I' Uncomment either line to suppress the warning. Is BOOST_PP_VARIADICS enabled by mistake for MSVC (especially 2013)? Should I explicitly set BOOST_PP_VARIADICS=0 for MSVC? Despite the warning, the code appears to work fine (i.e., the block of code gets properly called). Thanks, Filip #include <boost/version.hpp> #if defined(_MSC_VER) && BOOST_VERSION==105700 //#pragma warning(disable:4003) //#define BOOST_PP_VARIADICS 0 #endif #include <boost/scope_exit.hpp> #include <iostream> int main(int argc, char* argv[]) { int x=0; BOOST_SCOPE_EXIT((x)) { std::cout << "here " << x << std::endl; } BOOST_SCOPE_EXIT_END return 0; }

3 5

boost property tree for recursive structures
by Maurizio Vitale 10 Nov '14

10 Nov '14

Hello everybody, I'm trying to use the boost property tree library to represent recursive data structures, but although I can get the dumped json to look reasonable, I cannot traverse the ptree in any ways I've tried. The code below, compiles and run, except for the call to Dump in DumpAssign. Is there a way to traverse arbitrary trees where values can be themselves ptrees? I'm about to throw the towel and go with boost::seriaization, but I did like the traversal mechanisms property trees offer. Any suggestion? Thanks, Maurizio #include <boost/any.hpp> #include <boost/assign/list_of.hpp> #include <boost/foreach.hpp> #include <boost/property_tree/json_parser.hpp> #include <boost/property_tree/ptree.hpp> #include <boost/property_tree/xml_parser.hpp> #include <iostream> #include <string> #include <vector> #include <map> using boost::property_tree::ptree; using boost::assign::list_of; using boost::assign::map_list_of; using namespace std; ptree Op(string type, ptree a1, ptree a2) { ptree pt; // pt.put_value(type); pt.put("type", type); ptree args; args.push_back(make_pair("", a1)); args.push_back(make_pair("", a2)); pt.add_child("args", args); return pt; } ptree Net(string name) { ptree pt; pt.put("type", "net"); pt.put("name", name); return pt; } ptree Assign(ptree lhs, ptree rhs) { ptree pt; pt.put("type", "assign"); pt.add_child("lhs", lhs); pt.add_child("rhs", rhs); return pt; } string Dump(ptree::value_type e); string DumpConcat(ptree::value_type e) { string result = "{"; bool first = true; BOOST_FOREACH(const ptree::value_type& child, e.second.get_child("args")) { if (not first) { result += ", "; first = false; } result += Dump(child); } return result + "}"; } string DumpNet(ptree::value_type e) { return e.second.get<std::string>("name"); } string DumpAssign(ptree::value_type e) { string result = "assign "; // HOW TO HAVE A RECURSIVE CALL TO Dump(lhs) HERE? result += Dump(?); return result; } string DumpNop(ptree::value_type) {return "NOP";} string Dump(ptree::value_type e) { static std::map<string, string(*)(ptree::value_type)> dump = map_list_of ("net", DumpNet) ("concat", DumpConcat) ("assign", DumpAssign) ("nop", DumpNop) ; string type = e.second.get<string>("type", "nop"); return dump[type](e); } int main(int, char**) { ptree pt; ptree a1; a1.push_back(make_pair("", Assign( Op("concat", Op("concat", Net("a1"), Net("a1")), Net("w")), Net("a2")))); pt.add_child("operators", a1); cout << "=============\n"; write_json(std::cout, pt); cout << "=============\n"; BOOST_FOREACH(const ptree::value_type& e, pt.get_child("operators")) { cout << "> " << Dump(e); } }

1 0

Boost.Python shared_ptr bug?
by Christoff Kok 10 Nov '14

10 Nov '14

Hi, I found an issue when accessing a shared_ptr C++ object in Python using Boost.Python. When I try to access an attribute of the shared_ptr object read from an C++ object, I get an error telling me that the attribute does not exist. When I use raw pointers instead of shared_ptr, then there is no issue. Also, when using raw pointers, accessing an item in a list of base class objects returns the object in as the derived most class. This is wanted. When I use shared_ptrs however, the derived most object is of the base class type. This is not wanted. I am sure the Boost.Python developers should be aware of these two issues by now. If so, is there any plans to fix this? If so, when? Below is a test showing this issue: *Raw pointers:* #include<memory> #include<vector> struct Vehicle{ virtual ~Vehicle(){} int testAttribute; }; struct Boat: public Vehicle { virtual ~Boat(){} int testBoatAttribute; }; struct Garage { std::vector<Vehicle*>& vehicleList() { return m_VehicleList; } std::vector<Vehicle*> m_VehicleList; }; #include <boost/python.hpp> #include <boost/python/suite/indexing/vector_indexing_suite.hpp> BOOST_PYTHON_MODULE(garage_ext) { using namespace boost::python; class_<Garage>("Garage") .def("vehicleList", &Garage::vehicleList, return_internal_reference<1>()); class_<Vehicle,Vehicle*,boost::noncopyable>("Vehicle", no_init) .def_readwrite("testAttribute", &Vehicle::testAttribute); class_<Boat,Boat*,bases<Vehicle>>("Boat") .def_readwrite("testBoatAttribute", &Boat::testBoatAttribute); implicitly_convertible<Boat*, Vehicle*>(); class_<std::vector<Vehicle*> >("stl_vector_Vehicle_ptr") .def(vector_indexing_suite<std::vector<Vehicle*>>()); } *Shared pointers:* #include<memory> #include<vector> #include <boost/shared_ptr.hpp> struct Vehicle{ virtual ~Vehicle(){} friend bool operator==(const Vehicle& lhs, const Vehicle& rhs) { return true; } int testAttribute; }; struct Boat: public Vehicle { virtual ~Boat(){} friend bool operator==(const Boat& lhs, const Boat& rhs) { return true; } int testBoatAttribute; }; struct Garage { friend bool operator==(const Garage& lhs, const Garage& rhs) { return true; } std::vector<boost::shared_ptr<Vehicle>>& vehicleList() { return m_VehicleList; } std::vector<boost::shared_ptr<Vehicle>> m_VehicleList; }; #include <boost/python.hpp> #include <boost/python/suite/indexing/vector_indexing_suite.hpp> BOOST_PYTHON_MODULE(garage_ext){ using namespace boost::python; class_<Garage>("Garage") .def("vehicleList", &Garage::vehicleList, return_internal_reference<1>()); class_<Vehicle,boost::shared_ptr<Vehicle>,boost::noncopyable>("Vehicle", no_init) .def_readwrite("testAttribute", &Vehicle::testAttribute); class_<Boat,boost::shared_ptr<Boat>, bases<Vehicle>>("Boat") .def_readwrite("testBoatAttribute", &Boat::testBoatAttribute); implicitly_convertible<boost::shared_ptr<Boat>, boost::shared_ptr<Vehicle>>(); class_<std::vector<boost::shared_ptr<Vehicle>> >("stl_vector_Vehicle_ptr") .def(vector_indexing_suite<std::vector<boost::shared_ptr<Vehicle>>>()); } *Python test:* from garage_ext import * g = Garage() l = g.vehicleList() newboat = Boat() newboat.testAttribute = 3 newboat.testBoatAttribute = 5 l.append(newboat) print(type(l[0])) print(str(hasattr(l[0],"testAttribute"))) print(str(l[0].testAttribute)) b = l[0] print(type(b)) print(str(b.testBoatAttribute)) print("Done.") *Raw pointer result:* <class 'garage_ext.Boat'> True 3 <class 'garage_ext.Boat'> 5 Done. *Shared pointer result:* <class 'garage_ext.*Vehicle*'> *// Expected it to be Boat as with Raw pointers* Traceback (most recent call last): File "test_garage.py", line 9, in <module> print(str(hasattr(l[0],"testAttribute"))) *// Expected attribute to exist as with Raw pointers. Note: dir(l[0]) shows that it has the attribute. Accessing the attribute however throws an error.* Boost.Python.ArgumentError: Python argument types in None.None(Vehicle) did not match C++ signature: None(Vehicle {lvalue}) Kind Regards, Christoff

1 0

MSM library: documentation graphics
by Ricardo Cruz 09 Nov '14

09 Nov '14

Dear all, I am considering adopting boost MSM library for the statecharts in my project. It looks awesome. The documentation has several graphical representations of the state machines: http://www.boost.org/doc/libs/1_57_0/libs/msm/doc/HTML/index.html They look automatically generated. Are they? If so, what tool was used? I did not find that information anywhere in the documentation. Sorry if I miss it. Best wishes, Ricardo Cruz

2 1

Bidirectional breadth first search?
by Amanda Robson 08 Nov '14

08 Nov '14

Hi Does anyone know if Boost already supports bidirectional breadth first search? If not, how feasible would it be to extend boost’s bfs implementation to become bidirectional? Thanks. Amanda

1 0

iterator adaptor not inheriting pointer typedef
by Matei David 08 Nov '14

08 Nov '14

Hi, I have some questions about the Boost Iterator library. I've recently discovered the "hard way", meaning through impenetrable TMP error messages :), that when using boost::iterator_adaptor, the derived iterator type does not (always??) inherit the pointer typedef of the base iterator type. I mean, the iterator_adaptor glue class does not have this typedef. So, for example, I have a Base_Iterator type with: Base_Iterator::pointer != Base_Iterator::value_type* If I do: class Derived_Iterator : public boost::iterator_adaptor< Derived_Iterator, Base_Iterator > {...} then, strangely I find: Derived_Iterator::value_type == Base_Iterator::value_type (OK) Derived_Iterator::pointer == Base_Iterator::value_type* != Base_Iterator::pointer (not OK) I looked at the documentation, and I did find a mention of this, but only for iterator_facade, here: http://www.boost.org/doc/libs/develop/libs/iterator/doc/iterator_facade.html The corresponding page for iterator_adaptor does not mention the pointer typedef at all. While for facade using a plain pointer seems ok (no other reasonable default), I would argue that for adaptor this is not ok. Is this expected behaviour or a bug? Within the same setting, and in what could be a related issue, I also found that the intermediate boost::iterator_adaptor<> class does not seem to contain the default/common sense definition: Base_Iterator operator->() const { return this->base(); } I didn't look inside the source code of boost::iterator_adaptor, but I found a situation where I have to put this definition explicitly inside Derived_Iterator for my code to compile (without it, it doesn't). Does this sound like expected behaviour? Thanks M

2 2

Flyweight: constexpr user defined literals
by Akim Demaille 07 Nov '14

07 Nov '14

Hi all, Hi Joaquin, I'm using flyweights of strings (aka symbols) for my "format" arguments: a key that specifies the kind of output that should be produced by the printing routines. Sometimes, I have code that roughly resembles to: print_entry_(src, dst, o, dot2tex_ ? symbol("latex") : symbol("text")); My question is: do we have constexpr constructors with Flyweight in such a way that I could have something like: print_entry_(src, dst, o, dot2tex_ ? "latex"sym : "text"sym); and have a single construction of these guys not matter how many times I go throw this piece of code, or should I build them once for all in say a member? print_entry_(src, dst, o, dot2tex_ ? sym_latex : sym_text); I've seen nothing about "constexpr" in the doc.

2 1

Re: [Boost-users] iterator_facade Boost 1.57
by Matei David 07 Nov '14

07 Nov '14

On Tue, 04 Nov 2014 14:07:09 +0000 (UTC) gast128 wrote: > Dear all, > > Just trying out 1.57, since we are already 5 releases behind due to > all kinds of compilation errors with Boost and our software. Below > simplified code doesn't compile on vs2010: > > template <typename DerivedType> > struct IteratorFacade : public boost::iterator_facade<DerivedType, > int, std::random_access_iterator_tag> > { > typedef boost::iterator_facade<DerivedType, int, > std::random_access_iterator_tag> base; > > IteratorFacade (); > virtual ~IteratorFacade (); > > friend class boost::iterator_core_access; > > reference dereference () const; > }; > > struct MyIteratorFacade : IteratorFacade<MyIteratorFacade> > { > }; > > What do I wrong? Hi, I'm gcc 4.9.1 on Ubuntu 14.04. The reason this doesn't compile is that the "reference" typedef is contained in the glue class boost::iterator_facade, which is a base class of IteratorFacade<MyIteratorFacade>. When you write "reference" inside the later, the name is not being looked up in the base class. So you should write: typename base::reference dereference() const; If you want to use "reference" in many places in IteratorFacade<>, pull the typedef from its base with: typedef typename base::reference reference; or, if using C++11: using typename base::reference; Note: whether you pull it up or not, you can always get the typedef as IteratorFacade<...>::reference, or MyIteratorFacade::reference in your case. (See the example below, where I'm not pulling it up, but I can still find it.) I would also add the observation that your construct creates an unusual derivation. Usually, the iterator class you want to define has boost::iterator_facade as its direct base. In your case, boost::iterator_facade is the base of the base of your iterator class (so, 2 levels down): MyIteratorFacade : IteratorFacade<MyIteratorFacade> : boost::iterator_facade<MyIteratorFacade, ...> I'm not sure this would cause any problems, just be on the lookout for missing constructors. For example, this compiles just fine for me: #include <type_traits> #include <boost/iterator/iterator_facade.hpp> struct MyIteratorFacade : public boost::iterator_facade<MyIteratorFacade, int, std::random_access_iterator_tag> { typedef boost::iterator_facade<MyIteratorFacade, int, std::random_access_iterator_tag> base; MyIteratorFacade (); virtual ~MyIteratorFacade (); friend class boost::iterator_core_access; typename base::reference dereference() const; }; static_assert(std::is_same< MyIteratorFacade::value_type, int >::value, "MyIteratorFacade::value_type != int"); static_assert(std::is_same< MyIteratorFacade::reference, int& >::value, "MyIteratorFacade::reference != int&"); static_assert(std::is_same< MyIteratorFacade::pointer, int* >::value, "MyIteratorFacade::pointer != int*"); static_assert(std::is_same< std::iterator_traits<MyIteratorFacade>::value_type, int >::value, "iterator_traits<MyIteratorFacade>::value_type != int"); static_assert(std::is_same< std::iterator_traits<MyIteratorFacade>::reference, int& >::value, "iterator_traits<MyIteratorFacade>::reference != int&"); static_assert(std::is_same< std::iterator_traits<MyIteratorFacade>::pointer, int* >::value, "iterator_traits<MyIteratorFacade>::pointer != int*"); I compile with: g++ -Wall -Wextra -pedantic -std=c++11 -I${BOOST_INCLUDE_1_57} -c (I'm only using c++11 for static_assert.) M

1 0

Boost.Python C++ pointer object to python: Attribute does not exist.
by Christoff Kok 07 Nov '14

07 Nov '14

Hi, I'm struggling with the following issue in a boost.python implementation: I have a list of std::shared_ptr in C++, I am accessing this list from Python. - When I access an element in the list, the elements does not have any attributes apparently. I get an error trying to access an attribute, hasattr returns false on the attribute, but dir informs me that it exist. - When I change the C++ implementation from shared_ptr to raw ptr's everything works as expected. - I want to use shared_ptrs for what I feel: obvious reasons. Below is the C++ code and the Python code. ################### ### garage_ext.cpp ### ################### #include<memory> #include<vector> namespace boost { template<class T> T* get_pointer(std::shared_ptr<T>& p){ return p.get(); }} struct Vehicle{ virtual ~Vehicle(){} friend bool operator==(const Vehicle& lhs, const Vehicle& rhs) { return true; } int testAttribute; }; struct Boat: public Vehicle { virtual ~Boat(){} friend bool operator==(const Boat& lhs, const Boat& rhs) { return true; } int testBoatAttribute; }; struct Garage { friend bool operator==(const Garage& lhs, const Garage& rhs) { return true; } std::vector<std::shared_ptr<Vehicle>>& vehicleList() { return m_VehicleList; } std::vector<std::shared_ptr<Boat>>& boatList() { return m_BoatList; } std::vector<std::shared_ptr<Vehicle>> m_VehicleList; std::vector<std::shared_ptr<Boat>> m_BoatList; }; #include <boost/python.hpp> #include <boost/python/suite/indexing/vector_indexing_suite.hpp> class BoatWrap : public Boat, public boost::python::wrapper<Boat> { public: static std::shared_ptr<Boat> cast(std::shared_ptr<Vehicle> const& v) { return std::dynamic_pointer_cast<Boat>(v); } }; BOOST_PYTHON_MODULE(garage_ext) { using namespace boost::python; class_<Garage>("Garage") .def("vehicleList", &Garage::vehicleList, return_internal_reference<1>()) .def("boatList", &Garage::boatList, return_internal_reference<1>()) ; class_<Vehicle, std::shared_ptr<Vehicle>,boost::noncopyable>("Vehicle", no_init) .def_readwrite("testAttribute", &Vehicle::testAttribute) ; class_<BoatWrap,std::shared_ptr<Boat>,bases<Vehicle>>("Boat") .def("cast", &BoatWrap::cast) .staticmethod("cast") .def_readwrite("testBoatAttribute", &Boat::testBoatAttribute) ; implicitly_convertible<std::shared_ptr<Boat>,std::shared_ptr<Vehicle>>(); class_<std::vector<std::shared_ptr<Vehicle>> >("stl_vector_Vehicle_ptr") .def(vector_indexing_suite<std::vector<std::shared_ptr<Vehicle>> >()); class_<std::vector<std::shared_ptr<Boat>> >("stl_vector_Boat_ptr") .def(vector_indexing_suite<std::vector<std::shared_ptr<Boat>> >()); } ##################### ### Python test code ### ##################### g = Garage() l = g.boatList() newboat = Boat() l.append(newboat) boatFromList = l[0] print(type(boatFromList)) print(str(hasattr(newboat,"testBoatAttribute"))) dir(boatFromList) # The following line throws the error. print(str(hasattr(boatFromList,"testBoatAttribute"))) I created a cast method for boat. If I cast l[0] to Boat using: boatFromList = Boat.cast(l[0]) print(str(hasattr(boatFromList,"testBoatAttribute"))) works. This is all very strange to me. It feels very buggy. Could someone please help me clarify the reason for this behavious? Regards, Christoff

1 0

reference_wrapper on Boost 1.57
by gast128 06 Nov '14

06 Nov '14

This gives also a compilation error on vs2010: void F() { boost::reference_wrapper<float (* const)(float)> wrap(&cosf); //std::reference_wrapper<float (* const)(float)> wrap(&cosf); //ok } 1>KTestCuj2005June1.cpp(182): error C2248: 'boost::reference_wrapper<T>::reference_wrapper' : cannot access private member declared in class 'boost::reference_wrapper<T>' 1> with 1> [ 1> T=float (__cdecl *const )(float) 1> ] 1> C:\work sdk\boost_1_57_0\boost/core/ref.hpp(85) : see declaration of 'boost::reference_wrapper<T>::reference_wrapper' 1> with 1> [ 1> T=float (__cdecl *const )(float) 1> ] ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

1 1

Boost on Google+
by Vladimir Prus 06 Nov '14

06 Nov '14

Hi, I've created a Google+ community for Boost, and everybody is welcome to join here: https://plus.google.com/communities/106814259809358442744 I don't have any great plan here, but a lot of tech people are active on G+, so why not? -- Vladimir Prus CodeSourcery / Mentor Embedded http://vladimirprus.com

1 0

boost 1.57: MS VS2008: unknown pragma in type_index.hpp
by Andreas Wehrmann 05 Nov '14

05 Nov '14

Hi! I've just compiled boost 1.57 with MS VS2008 x86 and this warning came all over the place: main\lib\boost_1_57_0\boost\type_index.hpp(37) : warning C4068: unknown pragma Still, the compilation went fine and everything seems to work as usual. It's just somewhat annoying because this warning pops up very often when I compile my applications. Regards, Andreas

2 1

[Optional] Possible bug with VS2008
by dariomt＠gmail.com 05 Nov '14

05 Nov '14

Hi, The following minimal test case does not compile with VS2008 (using Boost 1.55) #include <boost/optional.hpp> struct A { int T; }; int main() { boost::optional<A> a; } The error is, edited for clarity: boost\optional\optional.hpp(479) : error C2523: 'A::~T' : destructor tag mismatch boost\optional\optional.hpp(479) : while compiling class template member function 'void boost::optional_detail::optional_base<T>::destroy_impl(boost::optional_detail::optional_base<T>::is_not_reference_tag)' with [ T=A ] boost\optional\optional.hpp(500) : see reference to class template instantiation 'boost::optional_detail::optional_base<T>' being compiled with [ T=A ] main.cpp(8) : see reference to class template instantiation 'boost::optional<T>' being compiled with [ T=A ] After much head-scratching, I found out the culprit: the name of the integer member!! The compiler confuses the name of member 'T' with the name of the template parameter 'T' when trying to invoke its destructor... The offending code is void destroy_impl ( is_not_reference_tag ) { get_ptr_impl()->T::~T() ; m_initialized = false ; } Given that I cannot change struct A, is there a way to fix this? Is this a compiler bug or a Boost.Optional bug? Thanks in advance!

1 0

Spirit with UI Tools
by Philipp Kraus 05 Nov '14

05 Nov '14

Hello, I would like to create a small parser with Boost.Spirit. I have run the short examples and everything works well, so I would like to create my own LL grammar. In my case I need also for documentation a EBNF or something else and in the best case I can would like to create the EBNF first and transform this into the Spirit LL grammar code. Did you know any tools to do this? My first idea is to use AntLR to create the grammar but imho it creates a LR grammar. Can you recommend a tool to define the grammar structure and generate the Spirit code? Thanks a lot Phil

3 6

Boost.Variant on Boost 1.57
by gast128 04 Nov '14

04 Nov '14

hello all, I get a compilation error with Boost.Operators and boost.Variant on vs2010: struct KFoo : boost::totally_ordered<KFoo> { }; bool operator<(const KFoo&, const KFoo&); bool operator==(const KFoo&, const KFoo&); void Foo() { boost::variant<KFoo> var; var.swap(var); } 1>C:\work sdk\boost_1_57_0\boost/variant/detail/move.hpp(60): error C2668: 'boost::swap' : ambiguous call to overloaded function 1> C:\work sdk\boost_1_57_0\boost/core/swap.hpp(54): could be 'void boost::swap<T,T>(T1 &,T2 &)' [found using argument-dependent lookup] 1> with 1> [ 1> T=T0, 1> T1=T0, 1> T2=T0 1> ] 1> C:\work sdk\boost_1_57_0\boost/variant/detail/move.hpp(44): or 'void boost::detail::variant::move_swap_fallback::swap<T,T>(T1 &,T2 &)' anyone?

1 0

bjam building with error
by NtVisigoth 04 Nov '14

04 Nov '14

Hello, I cannot compile bjam.exe and I see error. I have googled and I see my trouble here: Name: "Build.bat does not autodetect msvc on 64-bit Windows when building bjam" URL: https://svn.boost.org/trac/boost/ticket/1091 To reproduce: 0. cd <boos libraries directory> 1. Start cmd.exe. 2. Then start bootstrap.bat I see: d:\projects\cpp-workspace\boost-libraries>bootstrap.bat Building Boost.Build engine \\Vim\\vim74\\";c:\portable-programs\adt-bundle-windows-x86_64\sdk\\platform-tools;c:\portable-progr ams\adt-bundle-windows-x86_64\sdk\\tools" was unexpected at this time. d:\projects\cpp-workspace\boost-libraries\tools\build\src\engine> What can I do to compile bjam ?

1 0

problem with #include <boost/thread.hpp>
by Grison PG Pierre (External DEXIA-US) 04 Nov '14

04 Nov '14

Hello, I encounter a problem with the Thread library. The library works fine when I use it in a .exe project. It means it has been correctly built. Then I try to use the same library in an DLL project (so as to build a XLL object thanks to the XLW library). But as soon as I add the line #include <boost/thread.hpp> to my project, even if it compile without any problem, I get the following message when I debug my project through Excel: The file you are trying to open, "mylibrary.xll" is in a different format than specified by the file extension, Verify that the file is not corrupted [...]. Do you want to open the file now? And I can no more use my C++ functions in Excel. Do you have already encounter this problem? I use VS2010. I have tried both Multi-threaded Debug DLL (/MDd) and Multi-threaded DLL (/MD) options. My solution includes two other static libraries and also with the classic RunInterfaceGenerator XLW-project (the one which is executed when debugging). Regards, Pierre

2 1

iterator_facade Boost 1.57
by gast128 04 Nov '14

04 Nov '14

Dear all, Just trying out 1.57, since we are already 5 releases behind due to all kinds of compilation errors with Boost and our software. Below simplified code doesn't compile on vs2010: template <typename DerivedType> struct IteratorFacade : public boost::iterator_facade<DerivedType, int, std::random_access_iterator_tag> { typedef boost::iterator_facade<DerivedType, int, std::random_access_iterator_tag> base; IteratorFacade (); virtual ~IteratorFacade (); friend class boost::iterator_core_access; reference dereference () const; }; struct MyIteratorFacade : IteratorFacade<MyIteratorFacade> { }; What do I wrong?

1 0

Re: [Boost-users] Boost 1.57.0 has been released
by Tom Kent 04 Nov '14

04 Nov '14

> > Release 1.57.0 of the Boost C++ Libraries is now available. > These open-source libraries work well with the C++ Standard Library, and > are usable across a broad spectrum of applications. > The Boost license encourages both commercial and non-commercial use. > This release contains no new libraries and numerous enhancements and bug > fixes for existing libraries. > For details, including download links, see > http://www.boost.org/users/news/version_1.57.0 > You can also download directly from SourceForge: > http://sourceforge.net/projects/boost/files/boost/1.57.0/ > To install this release on your system, see > http://www.boost.org/doc/libs/release/more/getting_started/index.html > Thanks, > --The Boost release team > Vladimir Prus > Rene Rivera > Marshall Clow > Eric Niebler > Daniel James > Beman Dawes The corresponding windows binaries for msvc-8.0 (SP1), msvc-9.0 (SP1), msvc-10.0 (SP1), msvc-11.0 (Update 4) and msvc-12.0 (Update 3) in 32 & 64 bit versions are now also available from sourceforge. https://sourceforge.net/projects/boost/files/boost-binaries/1.57.0/ Tom Kent

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Re: [Boost-users] [Boost-announce] Boost 1.57.0 has been released
by Marshall Clow 04 Nov '14

04 Nov '14

> Hi Marshall, > > I wonder if the "Beta Issues” section on the release notes page (http://www.boost.org/users/history/version_1_57_0.html) is correct,… Looks like a copy-paste leftover from the beta version. Several people reported this. Thank you. It has been fixed. — Marshall

1 0

Boost 1.57.0 has been released
by Marshall Clow 03 Nov '14

03 Nov '14

Release 1.57.0 of the Boost C++ Libraries is now available. These open-source libraries work well with the C++ Standard Library, and are usable across a broad spectrum of applications. The Boost license encourages both commercial and non-commercial use. This release contains no new libraries and numerous enhancements and bug fixes for existing libraries. For details, including download links, see http://www.boost.org/users/news/version_1.57.0 You can also download directly from SourceForge: http://sourceforge.net/projects/boost/files/boost/1.57.0/ To install this release on your system, see http://www.boost.org/doc/libs/release/more/getting_started/index.html Thanks, --The Boost release team Vladimir Prus Rene Rivera Marshall Clow Eric Niebler Daniel James Beman Dawes

4 3

[Test] How to log output to both stdout in HRF and to a file in XML?
by Martin Ba 03 Nov '14

03 Nov '14

As asked on SO: http://stackoverflow.com/questions/26505229/how-to-log-boost-test-output-to… I would like to enable logging of Boost.Test output to *both* the stdout/sterr and to a logfile. However, I would also like to have the stdout logging be in HumanReadableFormat and only the file output be in XML format. Generating a report file seems to be addressed [here][1]. ([official docs][2]) Choosing the format can be done in [various ways][3], but it seems one is stuck with either HRF or XML? ----------- Rationale: When running tests on or [Jenkins][4] server, the [xUnit plugin][5] [requires][6] the **log** XML output (as opposed to the *report* XML output -- `log_level` vs. `report_level`). However, the in-progress log output (in HRF) is highly valuable *while* the tests are running on the server, to detect hanging tests or to a quick manual check of where the tests currently are. So I want an in-progress HRF log for the tests and at the end I need an XML file containing the `<TestLog>...</TestLog>` output of Boost.Test (not the `<TestResult>` output). Do note that we run both unit as well as integration tests via Boost.Test, so some of them are quite long-running. [1]: http://stackoverflow.com/questions/3786639/what-is-the-better-way-to-genera… [2]: http://www.boost.org/doc/libs/1_44_0/libs/test/doc/html/utf/user-guide/test… [3]: http://www.boost.org/doc/libs/1_44_0/libs/test/doc/html/utf/user-guide/runt… [4]: http://jenkins-ci.org/ [5]: https://wiki.jenkins-ci.org/display/JENKINS/xUnit+Plugin [6]: https://issues.jenkins-ci.org/browse/JENKINS-13686

2 1

ASIO: Windows/Linux/Mac socket inter-operability
by Joost Kraaijeveld 03 Nov '14

03 Nov '14

Hi, I have a C/S-application that uses ASIO-sockets. The application runs fine if I try to connect between 2 Windows or 2 Linus or 2 Mac machineas. However, it fails to work with a "reset by peer" error if I try to connect between Windows and Linux, Windows and Mac or Linux and Mac. Is there anything known about problems wrt inter-os connections, and if so, is there a solution for this? TIA -- Groeten, Joost Kraaijeveld Molukkenstraat 14 6524NB Nijmegen tel: 024-3607445 / 06-51855277

3 7

Boost IOStream - Buffer as an input stream
by Lloyd 03 Nov '14

03 Nov '14

Hi, We am trying to use a buffer as an input stream. For that we have used "basic_array_source" like this boost::iostreams::basic_array_source<BYTE> source(mem_ptr,size); boost::iostreams::stream<boost::iostreams::basic_array_source <BYTE>> streamReader; streamReader.open(source, std::ios::binary); But this method does not give input-stream related methods (functions like seekg), instead it give methods related to output stream (seekp). Can you please tell what is wrong with this approach? Thanks, Lloyd

1 0

[1.57.0] Release candidates available
by Marshall Clow 03 Nov '14

03 Nov '14

[ Please disregard previous message; apparently I am brain-dead this morning. The uploaded files are correct, though. ] Release candidate files for 1.57.0 are available at http://boost.cowic.de/rc/ As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. This helps ensure the candidates build OK before we push them out to SourceForge. The files (and associated md5s) are: MD5 (./boost_1_57_0_rc1.7z) = 17c98dd78d6180f553fbefe5a0f57d12 MD5 (./boost_1_57_0_rc1.tar.bz2) = 1be49befbdd9a5ce9def2983ba3e7b76 MD5 (./boost_1_57_0_rc1.tar.gz) = 25f9a8ac28beeb5ab84aa98510305299 MD5 (./boost_1_57_0_rc1.zip) = 5e040e578e3f0ba879da04a1e0cd55ff Thanks! -- The release managers P.S. Release notes are here: http://www.boost.org/users/history/version_1_57_0.html

3 3

[Asio] null_buffer behaviors
by lin li 03 Nov '14

03 Nov '14

Hi, guys. In the doc of asio, it says 'A null_buffers operation doesn't return until the I/O object is "ready" to perform the operation'. But when I use it on a server side socket, i.e. a socket created by "accept" call when a new connection has arrived. It seems to return immediately even the other end has not started to send the data yet. Is this normal?

1 0

How to know whether a boost heade has been included?
by Vincenzo Romano 03 Nov '14

03 Nov '14

I thought I could check for the symbol BOOST_VERSION to be defined. But, as of v1.55, it's not the case at least for the <boost/any.hpp> header. Any hint? Thanks in advance.

1 0

[boost.variant] accessing variant with pattern-matching instead of visitors
by Roger 02 Nov '14

02 Nov '14

Hi! The CppCon 2014, Yuriy Solodkyy had an interesting talk "Accept no visitors"(*). It presents an alternative accessing technique for variant data-type. It basically use pattern matching syntax, similar to that in functional languages, instead of visitors. I think this would be a great benefit for boost::variant data-type... being able to access variables from the same scope, group states similar in behavior, and take care of the loop unrolling for dispatching oneself. Especially when using variant as polymorphism, like the other interesting CppCon 2014 talking, Jason Lucas "Polymorphism with Unions" (**) covered. Would it be worth to implement a tiny pattern-matching library for boost::variant itself? Has anyone elaborated with this? Thanks for any hints! /perrog * Yuriy Solodkyy "Accept no visitors, http://youtu.be/QhJguzpZOrk ** Jason Lucas "Polymorphism with Unions", http://youtu.be/uii2AfiMA0o

1 0

(no subject)
by Johnny McCullough 01 Nov '14

01 Nov '14

I'm new to boost, and I'm wondering about the best / most efficient way to transfer a large dataset via boost::asio. I've retrieved a datasetfrom a database (Cassandra) and I'm using boost asio to provide a network service that responds to queries. So I have a client socket and a dataset. I have to iterate the dataset, perform some simple formatting (e.g. csv, json, xml), then write it out to the client socket. But there's a lot of data. Perhaps gigabytes. So my initial thoughts were the producer / consumer pattern - the producer writing to a streambuf and the consumer async_write-ing it out to the client's socket. But I'm not sure this is a good approach - I know that streambuf isn't threadsafe and so managing the streambuf with locks may well become a performance bottleneck. Obviously, I don't want to replicate what may be gigabyte(s) of data from a resultset into a buffer just so it can be written out to a socket, So should I write this data synchronously straight to the socket instead? What's the best approach to solving this kind of problem? thanks for your consideration

2 1