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[filesystem] boost::filesystem::copy
by Tim Blechmann 09 Dec '11

09 Dec '11

hi all, is there any reason, why boost::filesystem v3 does not provide the copy function? it seems to be implemented in namespace boost::filesystem3, but it is not pulled into namespace boost::filesystem. thanks, tim

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mail quotes color coding
by Maxim Yanchenko 09 Dec '11

09 Dec '11

Hi Boosters, If you're using one of web-based mailing list web-sites (like GMane or Google Groups), you may find this GreaseMonkey script useful: http://userscripts.org/scripts/show/92919 It adds coloring of different levels of quotation similar to lists.boost.org. Enjoy! Maxim

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[Regex] Calling convention for _MANAGED code still somewhat broken when mixing native and managed projects
by Martin B. 09 Dec '11

09 Dec '11

Hi there! Background ---------- The header boost/regex/config.hpp currently contains the following code: #if defined(BOOST_MSVC) && (BOOST_MSVC >= 1200) && defined(_MSC_EXTENSIONS) #if defined(_DEBUG) || defined(__MSVC_RUNTIME_CHECKS) || defined(_MANAGED) # define BOOST_REGEX_CALL __cdecl #else # define BOOST_REGEX_CALL __fastcall #endif # define BOOST_REGEX_CCALL __cdecl #endif the `|| defined(_MANAGED)` was added in 2006 (SVN history) to cater for the fact that __fastcall does not work on managed C++/CLI (/clr compiled) projects. See, e.g. this: http://lists.boost.org/boost-users/2004/12/9203.php Problem ------- This is really quite suboptimal, as with the solution as posted above, you need *a separate* lib/dll for managed-C++ and native-C++ Projects. Especially for the DLL, this is a non-solution, as I can only have one DLL for projects/modules that are used in the same application. _MANAGED is a define set by the VC compiler if the /clr switch is present, therefore it is actually never set when compiling the boost libraries. Of course you can set it via `define=_MANAGED` and you can then use these generated libraries from a C++/CLI project. (Which I have done: ... `define=_MANAGED` ... --with-regex ...) BUT: You can now *not* use these libraries from a non-managed ("native") C++ project as that, obviously, doesn't have _MANAGED set, and unlike with the boost build, I don't think it's feasible to define this wholesale for a native project. (And anyways, I'm rather hesitant to define this myself.) Obviously, I could just edit regex/config.hpp, but that is a maintenance nightmare of its own here. Solution -------- I *think* what really would be needed would be a define that the user could specify, something like this: #if defined(_DEBUG) || ... || defined(BOOST_REGEX_NO_FASTCALL) # define BOOST_REGEX_CALL __cdecl ... (I have attached a patch, hope this works.) Would this make sense? To add a short rationale: We use C++/CLI projects as bridges between managed and native modules of our application. In the C++ part, we use boost regexes, and sometimes it would make sense to reuse some native code in a C++/CLI bridge module. If this native code uses Boost.Regex, this doesn't work currently, as the native code file will also be compiled with /clr, and then we have a calling convention mismatch and can't use our boost-regex-dll. cheers, Martin

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[1.49.0] Schedule finalized
by Beman Dawes 08 Dec '11

08 Dec '11

The 1.49.0 schedule has been posted to the Boost C++ Libraries calendar. Milestones (all dates are Mondays): December 19: 1.49.0 (I.E. branches/release) Closed for new libraries. December 26: Quality checks begin January 9: Closed for major changes January 16: Closed for all changes January 23: Beta target date February 20: Release target date The longer period between the beta and release is intended to allow more time to respond to problem reports. --The Release Team

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[msm] deferral stack overfolw
by Richard Szabo 08 Dec '11

08 Dec '11

Hi Christophe just playing around with event deferral I have found a problem which leads to a stack overflow it ends in an infinite loop if I want to defer 2 events in the same state. see attached example it somehow similar to the problem we had earlier but that was fixed ... I have ran this test on MSM trunk version from yesterday. Cheers Richie

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[build] Little help required
by Antony Polukhin 08 Dec '11

08 Dec '11

Hi, I need to create Jamfile.v2 where one of the tests must be compiled on MSVC compilers with additional flag /Zc:wchar_t- How shall I change the following lines: test-suite conversion : # A lot of [ run ... ] lines [ run lexical_cast_typedefed_wchar_test.cpp ../../test/build//boost_unit_test_framework/<link>static ] # Requires /Zc:wchar_t- ; Best regards, Antony Polukhin

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Re: [boost] Boost.Math and Math Constants
by Brent Spillner 08 Dec '11

08 Dec '11

On Wed, 7 Dec 2011 15:33:21 Paul A. Bristow wrote: >John Maddock has now added a new cunning feature that allows the vast majority of users who just >want a built-in double to get the constants quickly as plain variables. So in non-template code, >users can write > > using boost::math::double_constants; > double area = pi * r * r; > >and users can read the equations easily. > >(Float and long double are similarly available in their own namespaces). It's a little bit of work up front, but if you define a custom type with separate overloads for each arithmetic operator/operand type combination (i.e. *(float), *(double), +(float), +(double), etc.) you should be able to offer a single namespace with constants that auto-promote (or demote) to the right type in expressions. That's also easily extensible to user-defined storage classes such as an extended precision float, and I think it's more maintainable since the using declaration (which is now untyped) can't get out of sync with the usage context. To prevent ambiguous overloads (in contexts where the constant itself is supplied as an argument to a polymorphic function, not in expressions), you can leave just one type (perhaps double) as implicitly castable-to, with explicit casts for the others. That seems more Boost-y to me, at any rate.

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[stl_ext_adv] ] Interest in advanced data structures
by Vadim Stadnik 08 Dec '11

08 Dec '11

Hi all, Advanced data structures (ADS) offer useful STL extensions that are not possible or not efficient with basic data structures, such as arrays, linked lists and red-black trees. The project https://github.com/vstadnik/stl_ext_adv http://dl.dropbox.com/u/51041088/stl_ext_adv_doc/index.html focuses mainly on a generalized and unified computer representation of sequences using the augmented B+ trees. It provides the following STL extensions: - The sequence container supports random access iterators and a union of interfaces of STL containers: vector, list and deque. This sequence offers the advantage of efficient update operations with logarithmic running time compared with linear running time of the same operations of std::vector. - The associative containers (set, multiset, map and multimap) with random access iterators. - The enhanced random access iterators effectively address the fundamental problem of the iterator invalidation. - The function accumulate() with logarithmic computational complexity can significantly improve performance of many practically important algorithms and applications, such as the numerical integration, the statistics, the data analysis etc. The examples demonstrate how to improve the computational complexity from O(N) to O(log N) in the following applications and problems: - numerical integration. - calculation of mean value and standard deviation; - calculation of weighted mean value; - testing if any number of consecutive elements are equal; - counting intersections of one interval with sequence intervals; Is there an interest in this project and implemented STL extensions? Interest in potentially useful, but not yet implemented algorithms and specialized containers: 1. The function accumulate() with constant computational cost. With this function some user algorithms, such as the numerical integration, can come close to the absolute theoretical limit of the computational cost. The function can be implemented through iterators enhanced with functionality of accumulators. For more details, see the section “Random access iterators” in the documentation. 2. The functions sequence::splice() with logarithmic running time in the worst case. Note that functions std::list::splice() provide in many cases constant computational cost, however, in the worst case the cost is linear. 3. Any other potentially useful specialized containers, iterators or algorithms? Augmented B+ trees are versatile and powerful data structures. They can be designed to maximize efficiency of particular algorithms and programming solutions. The limitation of specialized containers is that the computational cost of some other operations may increase. About augmented red black trees. The augmented red black trees can also support various STL extensions. The red black trees are yet out of the scope of this project for the reasons explained in the documentation. However, historically augmented red-black trees are probably the first ADS that could extend STL, since the method of augmenting red black trees was described as early as in 1990 [T.H. Cormen, C.E. Leiserson and R.L. Rivest.” Introduction to Algorithms” (1st ed.). MIT Press and McGraw-Hill, 1990]. This means, in particular, that the very first version of STL could provide associative containers with random access iterators. Also, as I understand the previously submitted project https://github.com/boost-vault/Containers/blob/master/countertree.zipimplem… containers based on the augmented red black trees. It is hardly possible to make an exact prediction, but without a doubt future versions of STL will benefit from advanced data structures. Regards, Vadim Stadnik

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boost.heap in trunk
by Tim Blechmann 07 Dec '11

07 Dec '11

hi all, i've imported my boost.heap library into trunk. it currently won't compile with gcc, but i've submitted patches against boost.parameter [1] and boost.fusion [2]. i hope they are applied, soon. i managed to integrate it into the documentation system, but it still needs to be integrated into the bug tracker and the regression test system. can i do that myself? tim [1] https://svn.boost.org/trac/boost/ticket/6214 [2] https://svn.boost.org/trac/boost/ticket/6215

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Re: [boost] c++11 and gcc 4.7
by Leo Goodstadt 07 Dec '11

07 Dec '11

> > From: Bruce Adams <tortoise_74(a)yahoo.co.uk> > Date: Tue, 6 Dec 2011 19:08:56 +0000 (GMT) > > Hi, > I am attempting to do a cost benefit analysis to justify adopting the > subset of C++11 that is supported by gcc 4.7. > As threads are one of the biggest features of c++11, I may be asked to > justify just boost.thread vs > gcc 4.7 + boost.thread. You may also wish to consider using a higher level threading library on top of std::thread / boost::thread. We have been using Intel Threading Building Blocks (http://threadingbuildingblocks.org/) for a while now, and it seems to live very happily alongside Boost. TBB means that you don't have to roll your own thread pools, or adjust the parallelism each time your programme is run. It is also a very thin layer in terms of efficiency. The modern trend across many programming languages also seems to move away from using (manual) synchronisation primitives whenever possible (just as "raw" new and delete has become rare in c++ over the past 20 years). TBB allows complex pipelines to be supported quite naturally in terms of a data flow. My only reservation is that it requires dynamic linking, which is not always desirable or even possible. Finally, the extra level of abstraction in TBB probably means that the onus on supporting varying standards of c++ 11 conformance falls on Intel and not you or your company! Leo

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Is there any interest in a library which solves C++ class reflection feature just like Java does?
by jinhua luo 07 Dec '11

07 Dec '11

Hi, In brief, I'd designed and implemented somehow C++ class reflection based on boost libraries. It has some unique advantages: a) it doesn't require code generator b) platform independent and compiler independent (I tested it on Windows and Linux, with vs2008 and gcc respectively) c) it's non-intrusive for the class definition, instead, you just need to declare and describe your class via some straightforward macros anywhere (header file or source file, and may be within any namespace), which also means you can wrap an external third-party library (which you have no way to touch the source codes) and reflects it classes. d) Cross shared library boundary, you can dynamic load the shared library and reflect the classes within it, without need to export any symbol manunally in C wrapper function way e) the API looks like Java reflection API Below is some codes snippet to have an overview of this library: -----libTest.cpp---start--- #include <iostream> #include <string> #include <boost/reflection/reflection.hpp> namespace test { class AccountItf { public: virtual std::string getId() const = 0; virtual void setId(std::string id) = 0; }; #define ACCOUNT_INTERFACE_REFL_DECLARE \ BOOST_REFL_INTERFACE(test::AccountItf) \ BOOST_REFL_CONST_METHOD(getId, std::string()) \ BOOST_REFL_METHOD(setId, void(std::string)) class Account : public AccountItf { std::string id; public: Account() : age(0) {} Account(std::string id, unsigned int age) : id(id), age(age) {} static void echo(Account* acct, std::string banner) { std::cout << banner + ": " << acct->getId() << std::endl; } std::string getId() const { return id; } void setId(std::string id) { this->id = id; } public: unsigned int age; }; //Account declaration for used by reflection //this declaration can be placed anywhere, even the header file BOOST_REFL_CLASS ( (test)(Account), //constructors BOOST_REFL_CONSTRUCTOR() BOOST_REFL_CONSTRUCTOR(std::string id, unsigned int age) //static methods BOOST_REFL_STATIC_METHOD(echo, void (Account* acct, std::string banner)) //properties BOOST_REFL_PROPERTY(age, unsigned int) //derived Inteface ACCOUNT_INTERFACE_REFL_DECLARE ) } -----libTest.cpp----end-- Compile the libTest.cpp into the libTest.dll or libTest.so. -----main.cpp----start-- #include <iostream> #include <string> using namespace std; #include <boost/reflection/reflection.hpp> using namespace boost::reflection; #if defined(BOOST_WINDOWS) #include <Windows.h> #else #include <dlfcn.h> #endif int main(int argc, char* argv[]) { #if defined(BOOST_WINDOWS) LoadLibraryA (argv[1]); #else dlopen(argv[1], RTLD_NOW); #endif Class t = Class::forName("test.Account"); boost::any obj = t.newInstance(std::string("Account-id-100"), (unsigned int)26); t.invokeStatic("echo", obj, std::string("TEST")); TypeInfoArray tArray; tArray.push_back(BOOST_REFL_TYPEID(std::string)); Method m1 = t.getMethod("setId", tArray); m1.invoke(obj, std::string("Account-id-200")); Method m2 = t.getMethod("getId"); boost::any ret = m2.invoke(obj); std::cout << "Account getId(): " << boost::any_cast<std::string>(ret) << std::endl; Property prop = t.getProperty("age"); prop.set(obj, (unsigned int)30); std::cout << "Account age: " << boost::any_cast<unsigned int>(prop.get(obj)) << std::endl; return 0; } -----main.cpp---end--- Compile the main.cpp into the executable and execute it: ./main libTest.dll it will output: TEST: Account-id-100 Account getId(): Account-id-200 Account age: 30 This library is very useful for framework-level design which needs C++ reflection, e.g. recently I'm working on somehow SQL mapping library for C++, just like MyBatis, and reflection makes possible to invoke the getter/setter of the object instances of classes specified in the XML file. Regards, JinHua

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c++11 and gcc 4.7
by Bruce Adams 06 Dec '11

06 Dec '11

Hi, I am attempting to do a cost benefit analysis to justify adopting the subset of C++11 that is supported by gcc 4.7. I believe there is a strong case for doing so from just the minor features and library improvements. However, I am having a hard time putting together a convincing cost benefit analysis (actually I would like to be able to do this with parts of boost too - any help with this would be great). I have many subjective arguments for boost, C++11 and TR1 but am tasked with trying to justifying any change in terms of costs and benefits. One of Boost's roles is to fill in gaps in c++ support where compiler vendors have not yet provided an implementation. I know that g++4.7 has incomplete support for multi-threading but it is unclear whether this is in the core language area and/or library area and what platforms it applies to. I am specifically interested in GNU/Linux. The status of boost for gcc4.7 is unclear (I know it has not been officially released yet but the status for gcc 4.6.2 is also unclear). Both of the following links from www.boost.org are several years and versions out of date http://www.boost.org/doc/libs/1_34_0/status/compiler_status.html http://boost.sourceforge.net/regression-logs/ Will boost.thread work as a drop in replacement for std::thread or is anything missing or broken on the core language side? (On the gcc side I am also interested in whether std::thread is a sufficiently complete implementation of the standard that boost.thread might not be necessary). The answer to this question may make my work harder. I was asked to justifiy either TR1, some part of boost or C++11 as my preference. I opted for C++11 as the most useful. I would probably have to justify boost libraries on a case by case basis. Justifying use of C++11 actually amounts to justifying a compiler upgrade + possibly training + possibly boost.thread As threads are one of the biggest features of c++11, I may be asked to justify just boost.thread vs gcc 4.7 + boost.thread. Surprisingly another thing that is unclear is the exact set of boost libraries that were included in C++11. I don't have either the standard (other than the February draft http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3242.pdf) or a good summary of the standard to hand. Suprisingly neither the boost website nor the g++ page have a list either, though the following two links are helpful: http://www.boost.org/doc/libs/1_48_0/?view=filtered_std-tr1 http://www.boost.org/doc/libs/1_48_0/?view=filtered_std-proposal I found a reference somewhere online (that I can no longer find) claiming, I believe incorrectly, that boost file_system is in C++11. This isn't mentioned on: http://www.boost.org/doc/libs/1_48_0/libs/filesystem/v3/doc/index.htm But nor its is presence in the 2005 "TR2" proposal. I worry that the 2005 TR2 proposal may be confused with any real TR2 proposal following on from C++11. I note that boost.chrono claims to be implemnting C++11 but I would have thought it was other way around and that the boost library was incorporated into the standard. http://www.boost.org/doc/libs/1_48_0/doc/html/chrono.html Anyway, the closest I've come to a list of libraries in C++11 outside of n3242 is: http://www2.research.att.com/~bs/C++0xFAQ.html#library Regards, Bruce.

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Re: [boost] Is there any interest in a library which solves C++ class reflection feature just like Java does?
by Brian Wood 06 Dec '11

06 Dec '11

Matus Chochlik on Tue, Dec 6, 2011 at 2:40 AM, jinhua luo <ljh.home.king(a)gmail.com> wrote: > Hi, > Hi, >> It has some unique advantages: >> a) it doesn't require code generator > Good, but it is not so unique Because C++ compiler is a code generator? [ ...] >> d) Cross shared library boundary, you can dynamic load the shared library >> and reflect the classes within it, without need to export any symbol >> manunally in C wrapper function way > I believe (and I have some expertise in using and implementing reflection > in C++ to base that belief upon) that the basic reflection should > compile-time and any run-time reflection should be built on top > of that. Agreed. -- Brian Wood Ebenezer Enterprises http://webEbenezer.net <http://webebenezer.net/> (651) 251-9384

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[chrono] steady_clock efficiency
by Kenneth Porter 06 Dec '11

06 Dec '11

I expect most people will use boost::chrono::steady_clock to measure performance. I've been considering switching from my raw calls to the Windows peformance counter APIs to the steady_clock. I'm a little worried about the overhead of what should be a non-intrusive facility. In examing the source, I see that steady_clock::now() reads the performance counter and then multiplies it by the reciprocal of the counter's frequency (acquired on first use of the clock) to return the time in nanoseconds. How expensive is this 64 bit multiply on a 32 bit system? How hard would it be to have now() return a time_point that stores the raw tick value and only converts it to nanoseconds when a calculation in real units is required? (Comparison to another time_point could still be done in performance counter ticks, saving the multiply.) Is it worth the extra complexity to demand-convert ticks to nanoseconds? Source is in boost_1_48_0\boost\chrono\detail\inlined\win\chrono.cpp

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Status of ISO/IEC TR 24733 library idea?
by Mateusz Łoskot 06 Dec '11

06 Dec '11

Hi, There is ISO/IEC TR 24733 draft on decimal floating-point arithmetic. I found old thread by Stefan Slapeta: Decimal floating point library [1] I wonder, what is status of this idea in Boost? [1] http://lists.boost.org/Archives/boost/2006/02/101457.php Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

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[release] Is Rlease branch is open for merge?
by Artyom Beilis 06 Dec '11

06 Dec '11

Hello, Is release brunch is open for merge of updates from trunk? Artyom Beilis -------------- CppCMS - C++ Web Framework: http://cppcms.sf.net/ CppDB - C++ SQL Connectivity: http://cppcms.sf.net/sql/cppdb/

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disable_if conundrum
by Marshall Clow 05 Dec '11

05 Dec '11

I have a function that returns a pair of iterators. There's also a version that takes a comparison predicate. template<class ForwardIterator, class Compare> std::pair<ForwardIterator, ForwardIterator> foo ( ForwardIterator first, ForwardIterator last ); template<class ForwardIterator, class Compare> std::pair<ForwardIterator, ForwardIterator> foo ( ForwardIterator first, ForwardIterator last, Compare comp ); I want to provide a range-based version of it. template<class Range> std::pair<typename boost::range_iterator<const Range>::type, typename boost::range_iterator<const Range>::type> foo ( const Range &r ); template<class Range, class Compare> std::pair<typename boost::range_iterator<const Range>::type, typename boost::range_iterator<const Range>::type> foo ( const Range &r, Compare comp ); Ok. There's a problem. If I call: foo ( first, last ) I get an error, because there are two perfectly good two argument candidates. Fine. Been there, seen that. I can use disable_if to make sure that the second range based version is only "active" when the arguments are different types. It's verbose, but it (usually) works template<class Range, class Compare> typename boost::disable_if_c<boost::is_same<Range, Compare>::value, std::pair<typename boost::range_iterator<const Range>::type, typename boost::range_iterator<const Range>::type> >::type foo ( const Range &r, Compare comp ); But this time it does not! I get a compile error telling me that the compiler can't deal with boost::range_iterator<XXX>::type, when XXX = some random iterator. It seems that the compiler wants to evaluate all the parameters of disable_if_c before deciding whether or not to SFINAE it (I guess that's not unreasonable, but it's not what I want) Apparently, all the other times that I did this, the return type of the function was not a dependent type of the template arguments. Any suggestions for a workaround here? -- Marshall -- Marshall Marshall Clow Idio Software <mailto:mclow.lists@gmail.com> A.D. 1517: Martin Luther nails his 95 Theses to the church door and is promptly moderated down to (-1, Flamebait). -- Yu Suzuki

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[enable_if] compile failure in trunk
by Tim Blechmann 05 Dec '11

05 Dec '11

trying to merge boost.heap into trunk, there is one issue, which seems to be triggered by the enable_if in the boost.heap testsuite. compiling with gcc (4.5 or 4.6), i get the following error: In file included from /home/tim/workspace/boost-trunk/boost/parameter.hpp:17:0, from /home/tim/workspace/boost-trunk/boost/heap/policies.hpp:12, from /home/tim/workspace/boost-trunk/boost/heap/detail/stable_heap.hpp:20, from /home/tim/workspace/boost_heap/libs/heap/test/../../../boost/heap/fibonacci_heap.hpp:20, from /home/tim/workspace/boost_heap/libs/heap/test/fibonacci_heap_test.cpp:8: /home/tim/workspace/boost-trunk/boost/parameter/name.hpp:52:1: error: template argument 2 is invalid In file included from /home/tim/workspace/boost-trunk/boost/fusion/support/detail/segmented_fold_until_impl.hpp:20:0, from /home/tim/workspace/boost-trunk/boost/fusion/sequence/intrinsic/detail/segmented_begin_impl.hpp:15, from /home/tim/workspace/boost-trunk/boost/fusion/sequence/intrinsic/detail/segmented_begin.hpp:10, from /home/tim/workspace/boost-trunk/boost/fusion/sequence/intrinsic/begin.hpp:17, from /home/tim/workspace/boost-trunk/boost/fusion/container/vector/vector10.hpp:15, from /home/tim/workspace/boost-trunk/boost/fusion/container/vector/vector_fwd.hpp:14, from /home/tim/workspace/boost-trunk/boost/fusion/container/vector/vector.hpp:10, from /home/tim/workspace/boost-trunk/boost/fusion/tuple/tuple.hpp:11, from /home/tim/workspace/boost-trunk/boost/fusion/tuple.hpp:10, from /home/tim/workspace/boost-trunk/boost/fusion/include/tuple.hpp:10, from /home/tim/workspace/boost-trunk/boost/math/tools/tuple.hpp:89, from /home/tim/workspace/boost-trunk/boost/math/special_functions/detail/igamma_inverse.hpp:13, from /home/tim/workspace/boost-trunk/boost/math/special_functions/gamma.hpp:1543, from /home/tim/workspace/boost-trunk/boost/math/special_functions/detail/bessel_jy.hpp:14, from /home/tim/workspace/boost-trunk/boost/math/special_functions/bessel.hpp:17, from /home/tim/workspace/boost-trunk/boost/math/special_functions.hpp:18, from /home/tim/workspace/boost-trunk/boost/random/generate_canonical.hpp:22, from /home/tim/workspace/boost-trunk/boost/random.hpp:52, from /home/tim/workspace/boost_heap/libs/heap/test/mutable_heap_tests.hpp:1, from /home/tim/workspace/boost_heap/libs/heap/test/fibonacci_heap_test.cpp:12: /home/tim/workspace/boost-trunk/boost/fusion/iterator/equal_to.hpp:77:9: error: expected nested-name-specifier before ‘enable_if’ /home/tim/workspace/boost-trunk/boost/fusion/iterator/equal_to.hpp:77:18: error: expected initializer before ‘<’ token /home/tim/workspace/boost-trunk/boost/fusion/iterator/equal_to.hpp:88:9: error: expected nested-name-specifier before ‘enable_if’ /home/tim/workspace/boost-trunk/boost/fusion/iterator/equal_to.hpp:88:18: error: expected initializer before ‘<’ token /home/tim/workspace/boost-trunk/boost/fusion/iterator/equal_to.hpp:98:31: error: ‘boost::fusion::iterator_operators::operator==’ has not been declared /home/tim/workspace/boost-trunk/boost/fusion/iterator/equal_to.hpp:99:31: error: ‘boost::fusion::iterator_operators::operator!=’ has not been declared In file included from /home/tim/workspace/boost-trunk/boost/fusion/iterator/segmented_iterator.hpp:13:0, from /home/tim/workspace/boost-trunk/boost/fusion/sequence/intrinsic/detail/segmented_begin.hpp:11, from /home/tim/workspace/boost-trunk/boost/fusion/sequence/intrinsic/begin.hpp:17, from /home/tim/workspace/boost-trunk/boost/fusion/container/vector/vector10.hpp:15, from /home/tim/workspace/boost-trunk/boost/fusion/container/vector/vector_fwd.hpp:14, from /home/tim/workspace/boost-trunk/boost/fusion/container/vector/vector.hpp:10, from /home/tim/workspace/boost-trunk/boost/fusion/tuple/tuple.hpp:11, from /home/tim/workspace/boost-trunk/boost/fusion/tuple.hpp:10, from /home/tim/workspace/boost-trunk/boost/fusion/include/tuple.hpp:10, from /home/tim/workspace/boost-trunk/boost/math/tools/tuple.hpp:89, from /home/tim/workspace/boost-trunk/boost/math/special_functions/detail/igamma_inverse.hpp:13, from /home/tim/workspace/boost-trunk/boost/math/special_functions/gamma.hpp:1543, from /home/tim/workspace/boost-trunk/boost/math/special_functions/detail/bessel_jy.hpp:14, from /home/tim/workspace/boost-trunk/boost/math/special_functions/bessel.hpp:17, from /home/tim/workspace/boost-trunk/boost/math/special_functions.hpp:18, from /home/tim/workspace/boost-trunk/boost/random/generate_canonical.hpp:22, from /home/tim/workspace/boost-trunk/boost/random.hpp:52, from /home/tim/workspace/boost_heap/libs/heap/test/mutable_heap_tests.hpp:1, from /home/tim/workspace/boost_heap/libs/heap/test/fibonacci_heap_test.cpp:12: /home/tim/workspace/boost-trunk/boost/fusion/container/list/cons.hpp:91:22: error: expected nested-name-specifier before ‘disable_if’ /home/tim/workspace/boost-trunk/boost/fusion/container/list/cons.hpp:91:32: error: expected ‘,’ or ‘...’ before ‘<’ token /home/tim/workspace/boost-trunk/boost/fusion/container/list/cons.hpp:122:18: error: expected nested-name-specifier before ‘disable_if’ /home/tim/workspace/boost-trunk/boost/fusion/container/list/cons.hpp:122:28: error: expected initializer before ‘<’ token compiling with gcc against 1.48 works fine. clang++ correctly compiles this code against boost-trunk. any idea, what could go wrong there? thanks, tim

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[units] - learning to use
by Janek Kozicki 05 Dec '11

05 Dec '11

Hi, I wrote a short function that integrates Huyghens spherical wave for diffraction. (This is a single slit experiment btw). I have some questions, marked with (*) double integral( const quantity<length> x // x - position where light intensity is calculated , const quantity<length> R // R - distance from slit to screen , const quantity<length> D // D - slit width , const quantity<length> lambda // lambda - wavelength , double steps // steps - number of integration steps // (*) ) { complex<double> i(0,1); complex<double> a(0); static const double pi = 3.14159265358979323846; // (**) quantity<wavenumber,complex<double> > k=2*pi/lambda; quantity<length> d=-0.5*D; // d - position on the slit quantity<length> dd=D/steps; // dd - width of integral step // integrate from -d to d: exp(i*k*r)/r for( ; d<= 0.5*D ; d+=dd ) { quantity<length> r=sqrt(pow<2>(R)+pow<2>(x-d)); a += (dd*exp(i*k*r)/r).value(); // (***) } return pow<2>(abs(a)); } (*) it should be `int steps` but if I write it this way I get a compilation error here: quantity<length> dd=D/steps; // dd - width of integral step That looks like a conversion problem. (**) why do I need to define pi ? I expected to find it somewhere, but I couldn't. (***) it seems strange that I need to take .value() here. The result is dimensionless, why can't it directly convert to complex<double> ? There is a risk that .value() would be expressed in millimeters or angstroms or whatever (maybe depending on dd), and then .value() would return a wrongly scaled number? Another question, why this works: quantity<length> wavelength ( 632.8 *nano*meters); and this does not? quantity<length> wavelength = 632.8 *nano*meters; Of course I know about extra copying, and waste of CPU resources on execution, when compiler isn't able to optimize this away (and usually it is able to do that). But why the heck this simple assignment can't work? PS: I am attaching a short test version of this program, it's in polish, but I hope you don't mind. best regards and thanks in advance for your help -- Janek Kozicki http://janek.kozicki.pl/ |

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New Container: Hashed Vector
by Sam Hertz 05 Dec '11

05 Dec '11

Boost Developers, Let me start by saying that I love the Boost Libraries. I use them frequently. Most of the time, when I need some unique data structure in my code, Boost can solve my problems. I saw the recent release of the Container library and I love the idea of the flat_set/map structures. In my code, I require a data structure that has fast associative lookup (like an unordered_set). However, this data structure should preserve the order of element insertion. In other words, the data structure would be similar to the flat_set/map structures, but would preserve order of insertion instead of relying on the < operator or a Comparable function object. Right now, I am calling this structure a hashed_vector. I am aware of Boost.Multi-Index, but this library is very general purpose and cumbersome to use to implement a hashed_vector. Ideally the structure would have an identical interface to the std::vector class, but with a much speedier find member function. Right now I am creating a wrapper class for multi_index_container to implement the hashed_vector, but hopefully a more direct implementation could be added to the Boost Libraries. I am sharing this idea with all of you because I want to see if you think such a structure is worth including in the libraries and if anyone is interested in implementing it. I would love to implement it myself, but I am currently a full-time graduate student and my experience with template programming is laughable when considering the amount currently used in the Boost Libraries. Looking forward to your feedback! Sam

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[smart-ptr][containers] type of the operator[] index
by Vicente J. Botet Escriba 05 Dec '11

05 Dec '11

Hi, which is the correct type used as index of operator[]. scoped_array uses std::ptrdiff_t. Others containers use std::size_t. The standard uses also std::size_t, but in 13.6 Built-in operators 13 For every cv-qualified or cv-unqualified object type T there exist candidate operator functions of the form T* operator+(T*, std::ptrdiff_t); T& operator[](T*, std::ptrdiff_t); T* operator-(T*, std::ptrdiff_t); T* operator+(std::ptrdiff_t, T*); T& operator[](std::ptrdiff_t, T*); we see again std::ptrdiff_t. When using an index to move from a scoped_array to another container which should be the type if the index? Best, Vicente

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[thread][general] Using and building the library
by Vicente J. Botet Escriba 04 Dec '11

04 Dec '11

Hi, there is a ticket for the Boost.Thread #4921 BOOST_THREAD_USE_DLL and BOOST_THREAD_USE_LIB are crucial and need to be documented (https://svn.boost.org/trac/boost/ticket/4921) related to the documentation of how the library can be used and build. Boost.Config provides some tools that the library authors can adopt, but is there a documented way to do it? If yet could you point it Here it is what could be added to for Boost.Thread Using and building the library Boost.Thread is configured following the conventions used to build libraries with separate source code (http://www.boost.org/doc/libs/1_48_0/libs/config/doc/html/boost_config/boos…) Boost.Thread will import/export the code only if the user has specifically asked for it, by defining either BOOST_ALL_DYN_LINK if they want all boost libraries to be dynamically linked, or BOOST_THREAD_DYN_LINK if they want just this one to be dynamically liked. The source code compiled when building the library defines a macros BOOST_THREAD_SOURCE that is used to import or export it. The user must not define this macro in any case. Best, Vicente

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[parameter] Boost.Graph program not responding at run-time
by Lorenzo Caminiti 03 Dec '11

03 Dec '11

Hello all, If I move the call to boost::depth_first_search into a template depth_first_search_impl and out of the Boost.Parameter function body, the code compiles (both MSVC and GCC with latest Boost from trunk) but the executable runs forever and prints nothing to cout... What am I doing wrong? #include <boost/parameter.hpp> #include <boost/graph/adjacency_list.hpp> #include <boost/graph/depth_first_search.hpp> #include <boost/graph/graph_traits.hpp> #include <boost/range/irange.hpp> #include <boost/pending/indirect_cmp.hpp> #include <boost/type_traits/is_convertible.hpp> #include <boost/type_traits/is_integral.hpp> #include <boost/type_traits/is_same.hpp> #include <boost/mpl/and.hpp> #include <boost/mpl/placeholders.hpp> #include <iostream> namespace graphs { template< typename G > struct vertex_descriptor { typedef typename boost::graph_traits<G>::vertex_descriptor type; }; template< typename T > struct is_incidence_and_vertex_list_graph : boost::mpl::and_< boost::is_convertible< typename boost::graph_traits<T>::traversal_category , boost::incidence_graph_tag > , boost::is_convertible< typename boost::graph_traits<T>::traversal_category , boost::vertex_list_graph_tag > > {}; template< typename T, typename Key > struct is_property_map_of_key : boost::is_same<Key, typename boost::property_traits<T>::key_type> {}; template< typename T, typename Key > struct is_integral_property_map_of_key { typedef typename boost::mpl::and_< boost::is_integral<typename boost::property_traits<T>::value_type> , is_property_map_of_key<T, typename Key::type> >::type type; static const bool value = type::value; }; template< typename Size, typename IndexMap > boost::iterator_property_map<boost::default_color_type*, IndexMap, boost::default_color_type, boost::default_color_type&> default_color_map ( Size const& num_vertices, IndexMap const& index_map ) { std::vector<boost::default_color_type> colors(num_vertices); return &colors[0]; } template< typename graph_type, typename visitor_type, typename root_vertex_type, typename index_map_type, typename color_map_type > void depth_first_search_impl ( graph_type graph, visitor_type visitor, root_vertex_type root_vertex, index_map_type index_map, color_map_type color_map ) { boost::depth_first_search(graph, boost::visitor(visitor). color_map(color_map).root_vertex(root_vertex). vertex_index_map(index_map)); } BOOST_PARAMETER_NAME(graph) BOOST_PARAMETER_NAME(visitor) BOOST_PARAMETER_NAME(root_vertex) BOOST_PARAMETER_NAME(index_map) BOOST_PARAMETER_NAME(color_map) BOOST_PARAMETER_FUNCTION( (void), depth_first_search, tag, (required (graph, *(is_incidence_and_vertex_list_graph<boost::mpl::_>)) ) (optional (visitor, *, boost::dfs_visitor<>()) (root_vertex, (vertex_descriptor<tag::graph::_>), *boost::vertices(graph).first) (index_map, *(is_integral_property_map_of_key< boost::mpl::_, vertex_descriptor<tag::graph::_> >), boost::get(boost::vertex_index, graph)) (in_out(color_map), *(is_property_map_of_key< boost::mpl::_, vertex_descriptor<tag::graph::_> >), default_color_map(boost::num_vertices(graph), index_map)) ) ) { return depth_first_search_impl<graph_type, visitor_type, root_vertex_type, index_map_type, color_map_type>(graph, visitor, root_vertex, index_map, color_map); } } // namespace graphs template< typename TimeMap > struct dfs_time_visitor : public boost::default_dfs_visitor { typedef typename boost::property_traits<TimeMap>::value_type T; dfs_time_visitor ( TimeMap dmap, TimeMap fmap, T& t ) : dmap_(dmap), fmap_(fmap), time_(t) {} template< typename V, typename G > void discover_vertex ( V u, G const& g ) const { put(dmap_, u, time_++); } template< typename V, typename G > void finish_vertex ( V u, G const& g ) const { put(fmap_, u, time_++); } private: TimeMap dmap_; TimeMap fmap_; T& time_; }; int main ( void ) { typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS> G; typedef boost::graph_traits<G>::vertices_size_type size_type; enum {u, v, w, x, y, z, N}; char names[] = {'u', 'v', 'w', 'x', 'y', 'z'}; typedef std::pair<int, int> E; E edges[] = {E(u, v), E(u, x), E(x, v), E(y, x), E(v, y), E(w, y), E(w, z), E(z, z)}; G g(edges, edges + sizeof(edges) / sizeof(E), N); std::vector<size_type> dtime(boost::num_vertices(g)); std::vector<size_type> ftime(boost::num_vertices(g)); size_type t = 0; dfs_time_visitor<size_type*> vis(&dtime[0], &ftime[0], t); graphs::depth_first_search(g, vis); std::vector<size_type> dorder(N); boost::integer_range<size_type> r(0, N); std::copy(r.begin(), r.end(), dorder.begin()); std::sort(dorder.begin(), dorder.end(), boost::indirect_cmp<size_type*, std::less<size_type> >(&dtime[0])); std::cout << "order of discovery: "; for(int i = 0; i < N; ++i) std::cout << names[dorder[i]] << " "; std::cout << std::endl; std::vector<size_type> forder(N); std::copy(r.begin(), r.end(), forder.begin()); std::sort(forder.begin(), forder.end(), boost::indirect_cmp<size_type*, std::less<size_type> >(&ftime[0])); std::cout << "order of finish: "; for(int i = 0; i < N; ++i) std::cout << names[forder[i]] << " "; std::cout << std::endl; return 0; } Thanks. --Lorenzo

2 6

Phoenix documentation problems
by Dave Abrahams 03 Dec '11

03 Dec '11

A few things I just noticed: 1. http://www.boost.org/doc/libs/release/libs/phoenix/doc/html/phoenix/what_s_… says: "Bind is no completely compatible with Boost.Bind" There's a letter missing after "no," the choice of which ("w" or "t") can invert the meaning of the sentence! It wasn't until I got to http://www.boost.org/doc/libs/release/libs/phoenix/doc/html/phoenix/modules… that I realized it was "w"! 2. On the same page I think there's a messed up cross-reference, because "phoenix.modules.function phoenix::function" Doesn't make a whole lot of sense. 3. On libs/phoenix/doc/html/phoenix/starter_kit/values.html I see: Confused? val(3) is a unary function, you say? Yes it is. No, it isn't. val is a unary function. val(3) *invokes* a unary function. 4. libs/phoenix/doc/html/phoenix/starter_kit/lazy_operators.html says that x[ref(i)] is an error but it gives only a confusing partial explanation that doesn't seem to follow the rules above it. operator[] looks as much like a binary operation as operator*; the difference is that the former must be a member. 5. Can we please, finally, *deprecate* Boost.Lambda and put a sign on its docs directing people to look at Phoenix? -- Dave Abrahams BoostPro Computing http://www.boostpro.com

4 3

[1.49.0] New libraries?
by Beman Dawes 03 Dec '11

03 Dec '11

What new libraries are ready for 1.49.0? What is that state of any new libraries that want to go in 1.49.0? Are they in trunk and do the developers think they are ready to be merged into release? The release managers would like to have a four week beta period of 1.49.0. That means we have to get going on new libraries right way if we are going meet our early February release schedule. --The release team

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