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[1.54.0] Beta Release Candidates available
by Marshall Clow 01 Jun '13

01 Jun '13

Release candidate files for 1.54.0 beta 1 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: 31266b7dcc6f557ad839e4e87317cd6e *boost_1_54_0_beta1_rc1.tar.gz fbf7be9cbaf9ea6fb21ae73d0c17100d *boost_1_54_0_beta1_rc1.tar.bz2 7de4299ab69c941e83fe3fc46dddc15f *boost_1_54_0_beta1_rc1.zip c73e5118ff585d9f1d68542f96a0758a *boost_1_54_0_beta1_rc1.7z Thanks, --The release managers

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[Xpressive] Nested patterns and sub-matches' semantic values
by Simon 30 May '13

30 May '13

Hi, For one part of a large project, I need to parse math and turn the "mathematical objects" into a C++ abstraction of them. Is it possible that a nested pattern hold semantic values within itself and can be queried for that value somehow? As if a match were a function of its sub-patterns' matches, if that makes sense... Code might speak better than my english: class math_number {...}; class math_addition {...}; class math_arglist {...}; class math_funcdef {...}; sregex integer = (s1= +_d) [ return math_number( as<int>(s1) ) ]; sregex addition = (s1= integer) >> '+' >> (s2= integer) [ return math_addition( as<math_number>(s1), as<math_number>(s2) ) ]; sregex arglist = (s1= identifier) >> *( ',' >> (s2= arglist)) [ std::vector<math_id> ids( as<math_arglist>(s2).begin(), as<math_arglist>(s2).end() ); ids.push_back(as<math_id>(s1)); return ids; ] sregex funcdef = ((s1= identifier) >> '(' >> (s2= arglist) >> ")=" >> (s3= addition)) [ return math_funcdef( as<math_id>(s1), as<math_arglist>(s2), as<math_addition>(s3) ) ]; I just want to avoid the funcdef above to be responsible for the construction of the various math_* objects the funcdef will hold (some of which will be complex to construct). And if I really must store the objects in an external stack, how should the parent-objects find their child-objects? Thanks, Simon

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Confused with BGL-- Six Degrees of Kevin Bacon example
by lizy10b 30 May '13

30 May '13

Hi there, I am new to BGL library. I am walking through the online tutorial and just finished the "10.2. Six Degrees of Kevin Bacon". As it is said at the end of the example: "Note that vertex descriptor objects can not always be used as indices into vectors or arrays such as bacon_number. This is valid with the adjacency_list class with VertexList=vecS, but not with other variations of adjacency_list. A more generic way to index based on vertices is to use the ID property map (vertex_index_t) in coordination with the iterator_property_map.". So I turn to have a look at the iterator_property_map page and its sample. First, this sample uses VertexList=vecS too. Second, I know this sample is using iterator_property_map to build a property map, but I think the property is still indexed by the edge descriptor objects. So what is the difference? Thanks. Zhiyu LI 2013-05-29 lizy10b

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[program options] parsing std::string
by Michael Powell 30 May '13

30 May '13

Hello, I want to parse std::string, perhaps into a vector<string>, but I do not want the command line argument to be positional in nature (i.e. like the examples demonstrate), because there may be a handful of parameters I need to capture into string or vector<string>. I've been able to parse integral types like int, even vector<int>, but haven't had much success with string. Possible or is this a program options "feature" and/or bug? Regards, Michael Powell

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Does the Proactor of boost uses edge-triggered epoll on linux?
by Journeyer J. Joh 30 May '13

30 May '13

Hello list, I have some questions about boost's async IO implementation for linux. 1. Does it use edge-triggered epoll to implement the Proactor (in terms of Reactor)? http://www.boost.org/doc/libs/1_53_0/doc/html/boost_asio/overview/core/asyn… The guide above says that boost's Proactor is implemented in terms of Reactor when it comes to Linux. If it is based on Reactor, I guess it should be level-triggered epoll. 2. Am I right? Then my question is 3. Does boost use edge-triggered epoll in any kind of async IO on linux? 4. Isn't edge-triggered epoll a good method to implement async IO on linux? Thank you very much. Sincerely Journeyer ---------------------------------------- Journeyer J. Joh o o s a p r o g r a m m e r a t g m a i l d o t c o m ----------------------------------------

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Install Boost.Build: gcc command not found (Windows)
by Tom C 29 May '13

29 May '13

I'm trying to build boost from sources following this guide: "http://www.boost.org/doc/libs/1_53_0/more/getting_started/windows.html#or-b…" I got the following outputs: here is bootstrap.log: here is my C:[...]\boost_1_53_0\tools\build\v2\user-config.jam: here is my PATH: It seems like the user-config.jam is not read by the bootstrap command. -- View this message in context: http://boost.2283326.n4.nabble.com/Install-Boost-Build-gcc-command-not-foun… Sent from the Boost - Users mailing list archive at Nabble.com.

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Re: How to Boost static lib build under Mountain Lion and XCODE 4.6
by B Hart 27 May '13

27 May '13

Hi, I'm trying to install and use Boost 1_53_0 on MAC OS X Mountain Lion and use it with the latest XCODE 4.6.x. I want to port a small MS VS MFC C++ app. I developed on Windows to MAC. Specifically I need to install and build boost as static libraries. I'm completely new to programming on the MAC side of things. I understand that XCODE now uses LLVM Clang, with libc++ and not GCC. I've used GCC on Linux. I started following the instructions at: http://www.boost.org/doc/libs/1_53_0/more/getting_started/unix-variants.html but quickly ran into trouble. Does anyone have detailed instructions for how to install and compile boost statically under Mountain Lion and XCode 4.6? Below is the terminal input and output showing how far I got. Thanks. Terminal IO: ./bootstrap.sh --with-bjam=BJAM --with-toolset=TOOLSET users-Mac-mini:boost_1_53_0 user$ ./bootstrap --with-bjam=BJAM --with-toolset=TOOLSET -bash: ./bootstrap: No such file or directory users-Mac-mini:boost_1_53_0 user$ ./bootstrap.sh --with-bjam=BJAM --with-toolset=TOOLSET -n Detecting Python version... 2.7 -n Detecting Python root... /System/Library/Frameworks/Python.framework/Versions/2.7 -n Unicode/ICU support for Boost.Regex?... not found. Generating Boost.Build configuration in project-config.jam... Bootstrapping is done. To build, run: ./b2 To adjust configuration, edit 'project-config.jam'. Further information: - Command line help: ./b2 --help - Getting started guide: http://www.boost.org/more/getting_started/unix-variants.html - Boost.Build documentation: http://www.boost.org/boost-build2/doc/html/index.html users-Mac-mini:boost_1_53_0 user$ ./b2 link=static threading=multi toolset=darwin cxxflags="-arch i386 -arch x86_64" macosx-version=10.6 stage -bash: ./b2: No such file or directory

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Using boost.Test check_is_small for my own
by Olaf Peter 26 May '13

26 May '13

Hello, I try to use parts of boost.test lib not for unit testing self but inside an algorithm. Anyway, at the end of header http://www.boost.org/doc/libs/1_53_0/boost/test/floating_point_comparison.h… this is written inside anonymous namespace it works obviously, but not at me. What happened here and how to fix it? Did I not read the header carefully? Thanks, Olaf ---8<---- #include <boost/test/floating_point_comparison.hpp> namespace tools { using boost::test_tools::check_is_small_t; check_is_small_t const& check_is_small = unit_test::ut_detail::static_constant<check_is_small_t>::value; } int main() { bool ok = tools::check_is_small(900, 0.1); } --->8---- test.cpp:5:30: error: 'boost::test_tools::check_is_small_t' has not been declared test.cpp:7:5: error: 'check_is_small_t' does not name a type test.cpp: In function 'int main()': test.cpp:12:15: error: 'check_is_small' is not a member of 'tools'

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variant visitor using SFINAE problem
by Olaf Peter 26 May '13

26 May '13

Hi, attached my code to show my problem. It seems to work (partially) so far, but not the vector<int> where I get a compile error. This is my first try with SFINAE in that way. Are the conditions correct and robust enough? How to compile it? Did I forgot one use case? Using this small helper would simplify some post processing. Thanks, Olaf

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[thread] "almost works" clarification
by Michael Powell 26 May '13

26 May '13

Hello, Okay, so without starting a flame war, because that is not my intention... Also bear in mind, I am coming from an informed C# .NET frame of mind having worked with .NET threading, synchronization, events, and so forth. I ran across this article, which although a bit dated, is a pretty good sketch of what I would consider a fairly robust thread runner abstraction, which if you read past the frustration, makes good sense, at least in my opinion: http://peter.bourgon.org/blog/2008/12/12/boost-thread-kindof-sucks.html. Nothing against the author, I might turn that around and couch it instead: boost-thread-almost-works: in the sense that, while there are indeed a rich set of primitives provided to hide the details of pthread, Win32 threading, or what have you, it stops just short of providing that abstraction layer for what Peter and I (probably just he and I) consider a robust runner, monitor, and worker. The ingredients are there, though, and with a little bit of persuading, can compose a fairly robust little set of threaded runners. Okay, with that said, am I correct in understanding, the combination of condition and mutex facilitates the analog to C# .NET AutoResetEvent or ManualResetEvent (loosely, ResetEvent) type thing? In other words, thread keeps-on-a-runnin' until condition is notified, at which point thread loop(s) know to stop working when they check in with their conditioned mutex? In other words, mechanically speaking, a worker-bee that starts obtains a lock on the mutex. While the worker is running, on-lookers may poll the monitor for thread completion (which times out as long as the worker-bee is running and has a scoped lock), or otherwise signal the thread to complete through the notify mechanism (which tells the worker-bee to return, which clears the lock). The worker-bee runs until it is completed or its conditioned mutex has been notified (whichever comes first). In another rendition, I was actually using the thread-interruption mechanism, which I may still do, is another way of signaling a thread that it should stop what it's doing. However, seems a bit less graceful than routing requests through a formalized abstraction layer I think, except through creative use of interrupt disabled (which I was also using), but is something else to consider. Anywho, food for thought. Comments, critiques welcome. Thank you... Regards, Michael Powell

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