June 2011 - Boost-users - lists.preview.boost.org

Directory Iterator / Directory "access denied" exception
by Kiah08 24 Jun '11

24 Jun '11

Does anyone know of a way to handle exceptions when a directory is inaccessible? I would like to be able to resume the directory scan after the inaccessible directory. Please give an in depth example if possible. Using Boost 1.46. -- View this message in context: http://boost.2283326.n4.nabble.com/Directory-Iterator-Directory-access-deni… Sent from the Boost - Users mailing list archive at Nabble.com.

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Graph Isomorphism
by Evan Driscoll 24 Jun '11

24 Jun '11

I am writing a library for a variant of finite automata. States in the automata are named by "keys", which boil down to unsigned ints. For testing purposes, I'd like to be able to test whether two automata are isomorphic -- i.e. they are the same except for perhaps different keys for the corresponding states. (The motivation for this is that there are a few operations like 'determinize' that I don't want to guarantee any particular names for the output states, but I want or need to test something stronger than language equality between the actual and respected result.) One way I've thought of doing this is to convert the transition graph of each automaton to a BGL graph and use it's 'isomorphism' function to determine whether the two are isomorphic. However, I'd need to impose two extra conditions: - Edges between nodes are labeled (with the symbol that makes the automaton take that transition), and I need to make sure these match between the two graphs - Nodes are labeled (with whether they correspond to an initial and accepting state of the automaton), and I need to make sure these match up between the two graphs Does it sound like this task is something the BGL is suited for? Thanks, Evan Driscoll

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compile error with boost trunk and clang trunk
by Dane Springmeyer 23 Jun '11

23 Jun '11

Anyone else running latest clang and boost and running into compile errors? I'm hitting a problem with __is_pod in type traits. More details here: https://svn.boost.org/trac/boost/ticket/5635 Let me know if there is anything else I can test to make sure its not something special about my setup. Dane

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[boost 1.42, gcc 4.4, ubuntu 10.10] Program hangs when using barrier.wait() even though all threads have reached wait.
by Gareth 23 Jun '11

23 Jun '11

I'm having problems with boost::barrier. I've written a class that creates a thread pool to map evaluate an array of functions to an array of results. I've used barriers in the synchronisation. The problem is that the threads are all getting stuck at the barrier::wait calls. I've verified with gdb that all the worker threads and the manager thread are sitting in barrier::wait() however, there all stuck. I have no idea what's causing this. I've put the source code in the following github gist and also pasted it to the end of the email. https://gist.github.com/1041351 I've also checked the bugs list for any known bugs, fixed or otherwise, to do with threading and I haven't found anything. I'm not sure what I'm doing wrong. -Gareth Charnock /* compile: g++ thread_template.cpp -lboost_thread Outputs: BOOST_VERSION = 104200 Starting thread 0 Starting thread 1 Thread 0 waiting for work Thread 1 waiting for work Threads have work... */ #include <boost/version.hpp> #include <boost/thread.hpp> #include <boost/thread/barrier.hpp> #include <boost/function.hpp> #include <iostream> #include <vector> template<typename T> class Multithreader { public: Multithreader() : numCPU(sysconf(_SC_NPROCESSORS_ONLN)), _barrier(numCPU+1), mFuncs(NULL), mMapTo(NULL) { std::cout << "BOOST_VERSION = " << BOOST_VERSION << std::endl; //Start the thread pool for(long i = 0;i<numCPU;i++) { std::cout << "Starting thread "<<i<< std::endl; boost::thread(WorkerThread(i,this)); } } ~Multithreader() { //Terminate the threads //todo } void map(const std::vector<boost::function<T ()> >& funcs,std::vector<T>& mapTo) { mFuncs = &funcs; mMapTo = &mapTo; std::cout << "Threads have work..." << std::endl; _barrier.wait(); //Workers are working at this point std::cout << "Threads are working..." << std::endl; _barrier.wait(); std::cout << "Threads have finished" << std::endl; } private: const std::vector<boost::function<T ()> >* mFuncs; std::vector<T>* mMapTo; boost::barrier _barrier; size_t numCPU; class WorkerThread { public: WorkerThread(long _id,Multithreader* _parent) : id(_id),parent(_parent) { } void operator()() { while(true) { std::cout << "Thread "<<id<<" waiting for work" << std::endl; parent->_barrier.wait(); std::cout << "Thread "<<id<<" has work" << std::endl; //Do work for(long i = id;i<parent->mFuncs->size();i+=parent->numCPU) { parent->mMapTo->at(i) = parent->mFuncs->at(i)(); } parent->_barrier.wait(); std::cout << "Thread "<<id<<" finished the work" << std::endl; } } long id; Multithreader* parent; }; }; #include <boost/bind.hpp> double f(double x) { return x*2; } int main() { //Start the thread pool Multithreader<double> mt; std::vector<boost::function<double()> > work;work.resize(20); std::vector<double> results;results.resize(20); //Prepare the work for(unsigned long i = 0;i<20;i++) { work[i] = boost::bind(f,i); } //Execute in parallel mt.map(work,results); while(true) { //For the purposes of the example, keep the main thread alive //so we don't delete mt } }

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Ensuring same locale for reading/writing
by Szymon Gatner 23 Jun '11

23 Jun '11

Hi, My original question comes from Random library but I guess it is not strictly Random-related. I would like to save a state of pseudo-random number generator and then restore it on different machine with potentially different locale. Random docs say tho: "The state shall be written in a platform-independent manner, but it is assumed that the locales used for writing and reading be the same." How do I assure same locale on all machines / platforms? Or more directly: how do I assure portable save/restore. -- Szymon Gatner The Lordz Games Studio www.thelordzgamesstudio.com

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[multi-index] using std::distance() with ordered indices
by dv 23 Jun '11

23 Jun '11

Hello, I need to find out the size of a range defined by two ordered_non_unique iterators . Right now I just use std::distance() for this, however, the time complexity in this case is O(n). Is there some special way for calculating distances between multi-index container iterators? regards

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BGL: Get a bundled property for a particular edge_descriptor
by David Doria 22 Jun '11

22 Jun '11

Consider this setup: struct MyProperty { int MyIntProperty; }; typedef adjacency_list<vecS, vecS, undirectedS, MyProperty, MyProperty> Graph; Graph g; Graph::vertex_descriptor v0 = add_vertex(g); Graph::vertex_descriptor v1 = add_vertex(g); Graph::vertex_descriptor v2 = add_vertex(g); std::pair<Graph::edge_descriptor, bool> e01 = add_edge(v0, v1, g); Now I want to get the bundled propery corresponding to e01. I tried this: property_map<Graph, int MyProperty::*>::type MyIntPropertyMap = get(&MyProperty::MyIntProperty, g); cout << MyIntPropertyMap[e01.first]; but the compiler complains about no matching operator[]. Any suggestions? I thought I had examples of all of these simple things, but I guess I'm missing at least one :) David

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bjam install location
by David Doria 22 Jun '11

22 Jun '11

I ran this: ~/src/boost$ ./bootstrap.sh ~/src/boost$ ./bjam --prefix=/home/ddoria/bin The output was: The Boost C++ Libraries were successfully built! The following directory should be added to compiler include paths: /home/ddoria/src/boost The following directory should be added to linker library paths: /home/ddoria/src/boost/stage/lib I would have expected these to be more like /home/ddoria/bin/bin and /home/ddoria/bin/lib - am I misunderstanding the install process? Thanks, David

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how to build boost using mingw on windows?
by Ákos Maróy 22 Jun '11

22 Jun '11

Hi, This might be a frequent question asked, but I can't seem to find a proper response. I'm trying to build boost using the current version of mingw, from under msys, but I can't seem to make it work. I tried boost 1.45.0 and 1.46.1 as well. here are my results: boost 1.45.0: akos@RAKKU /c/Users/akos/src/boost_1_45_0 $ ./bootstrap.sh --with-toolset=mingw --prefix=/c/Users/akos/usr Building Boost.Jam with toolset mingw... tools/build/v2/engine/src/bin.ntx86/bjam Unicode/ICU support for Boost.Regex?... not found. Backing up existing Boost.Build configuration in project-config.jam.3 Generating Boost.Build configuration in project-config.jam... Bootstrapping is done. To build, run: ./bjam To adjust configuration, edit 'project-config.jam'. Further information: - Command line help: ./bjam --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 akos@RAKKU /c/Users/akos/src/boost_1_45_0 $ ./bjam mingw.jam: No such file or directory c:/Users/akos/src/boost_1_45_0/tools/build/v2/build\toolset.jam:38: in toolset.u sing rule mingw.init unknown in module toolset. c:/Users/akos/src/boost_1_45_0/tools/build/v2/build\project.jam:881: in using project-config.jam:12: in modules.load c:/Users/akos/src/boost_1_45_0/tools/build/v2\build-system.jam:257: in load-conf ig c:/Users/akos/src/boost_1_45_0/tools/build/v2\build-system.jam:423: in load-conf iguration-files c:/Users/akos/src/boost_1_45_0/tools/build/v2\build-system.jam:554: in load c:\Users\akos\src\boost_1_45_0\tools\build\v2/kernel\modules.jam:283: in import c:\Users\akos\src\boost_1_45_0\tools\build\v2\kernel\bootstrap.jam:142: in boost -build c:\Users\akos\src\boost_1_45_0\boost-build.jam:17: in module scope when trying boos 1.46.1: akos@RAKKU /c/Users/akos/src/boost_1_46_1 $ ./bootstrap.sh --with-toolset=mingw --prefix=/c/Users/akos/usr Building Boost.Jam with toolset mingw... tools/build/v2/engine/src/bin.ntx86/bja m Unicode/ICU support for Boost.Regex?... not found. Generating Boost.Build configuration in project-config.jam... Bootstrapping is done. To build, run: ./bjam To adjust configuration, edit 'project-config.jam'. Further information: - Command line help: ./bjam --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 akos@RAKKU /c/Users/akos/src/boost_1_46_1 $ ./bjam mingw.jam: No such file or directory c:/Users/akos/src/boost_1_46_1/tools/build/v2/build\toolset.jam:38: in toolset.u sing rule mingw.init unknown in module toolset. c:/Users/akos/src/boost_1_46_1/tools/build/v2/build\project.jam:886: in using project-config.jam:12: in modules.load c:/Users/akos/src/boost_1_46_1/tools/build/v2\build-system.jam:257: in load-conf ig c:/Users/akos/src/boost_1_46_1/tools/build/v2\build-system.jam:423: in load-conf iguration-files c:/Users/akos/src/boost_1_46_1/tools/build/v2\build-system.jam:554: in load c:\Users\akos\src\boost_1_46_1\tools\build\v2/kernel\modules.jam:283: in import c:\Users\akos\src\boost_1_46_1\tools\build\v2\kernel\bootstrap.jam:142: in boost -build c:\Users\akos\src\boost_1_46_1\boost-build.jam:17: in module scope trying other settings, e.g. a toolset of gcc will not work :( trying the bootstrap.bat file with the same command line parameters don't work, as they expect to find the MS C++ compiler, cl. I googled this issue, but did not find a solution that would eventually work :( I wonder what the proper process is to build boost on Windows using the current version of MingW. Akos PS: the gcc version I have is: $ gcc --version gcc.exe (GCC) 4.5.2 Copyright (C) 2010 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

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boost 1.45.0 regression tests.
by Jason Nye 22 Jun '11

22 Jun '11

Hello All, Platform/toolset information: Windows, MSVC9.0, primarily 64-bit but we do have 32-bit, _SECURE_SCL=0 My company is using boost 1.45.0 and we build boost ourselves. We have a policy that for any off-the-shelf software we build from source, we run the unit tests for that package to verify a basic level of usability. When running the tests for all libraries (by using a script to CD into their respective 'test' directories and running bjam), most pass but I do get a few failures. The bjam command line I'm using for each is: bjam.exe --build-dir=%BOOST_ROOT%\..\build_x64_tests --user-config=%BOOST_ROOT%\user-config.jam link=shared address-model=64 cxxflags=/D_SECURE_SCL=0 The user-config.jam simply forces the use of the msvc90 toolset. -------------------------------------------------------------------------------------- The results: Lexical Cast ============ ... lexical_cast_loopback_test.cpp(74): error in "test_round_conversion_double": check magic_msvc == lexical_cast<T>(magic_msvc_s) failed lexical_cast_loopback_test.cpp(74): error in "test_round_conversion_long_double": check magic_msvc == lexical_cast<T>(magic_msvc_s) failed tr1.random ========== ... unknown location(0): fatal error in "test_main_caller( argc, argv )": This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information. run_random.cpp(48): last checkpoint C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\../include/random(850): invalid argument for subtract_with_carry[_01]::seed *** 1 failure detected in test suite "Test Program" -------------------------------------------------------------------------------------- Does anyone know what might be the cause of these failures? Maybe I'm running the tests incorrectly? Keep in mind that we absolutely need certain compiler flags - running bjam by itself will choose the wrong compiler, address model and _SECURE_SCL flags. Any help would be greatly appreciated. Regards, Jason ______________________________________________________________________________________________ [cid:image002.png@01CC3001.C8AE2BE0] Jason Nye | Principal Software Engineer 5850 Opus Parkway, Suite 300 l Minnetonka, MN 55343 952.487.9693 l 866.433.4624 l www.vitalimages.com<http://www.vitalimages.com/> A Toshiba Medical Systems Group Company ______________________________________________________________________________________________

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