March 2008 - Boost-users - lists.boost.org

Random: Using random generators with runtime parameters
by Hans Mull 23 Nov '08

23 Nov '08

Hi! How can I use random generators with multiple parameters such as linear_congruential with parameters that are only known at runtime? Thanks in advance, Hans

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boost::program_options
by Duy Nguyen 09 Oct '08

09 Oct '08

When I try to use the boost::program_options library to read a property file, I got the error when I run "make" on Cygwin (I installed Cygwin on WIndows XP). > make g++.exe -I /cygdrive/c/MyTest/Test1/include/boost-1_34_1/ -c TestInit.cpp Test.cpp TestDriver.cpp g++.exe -I /cygdrive/c/MyTest/Test1/include/boost-1_34_1/ -c TestInit.cpp Test.cpp TestDriver.cpp g++.exe -I /cygdrive/c/MyTest/Test1/include/boost-1_34_1/ -c TestInit.cpp Test.cpp TestDriver.cpp g++.exe TestInit.o Test.o TestDriver.o -o "TestDriver" -L/cygdrive/c/MyTest/Test1/lib -lboost_program_options-gcc34-mt-d-1_34_1 -lg2c Info: resolving vtable for boost::program_options::variables_mapby linking to __imp___ZTVN5boost15program_options13variables_mapE (auto-import) Then when I run my program, it does not work. If I comment out the "try ... catch" block which uses the boost::propram_options library then it compiles and works fine. Please show me how to fix it. Thank you.

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boost::filesystem exception not caught on MacOS X
by Lothar May 21 Sep '08

21 Sep '08

Hi, I have a strange problem that an exception thrown by a boost::filesystem directory_iterator is not caugth on MacOS X. Please consider the following code: ("const string &dir" is a parameter) bool retVal = true; try { directory_iterator i(dir); directory_iterator end; while (i != end) { // do something ++i; } } catch (...) { retVal = false; } While this works perfectly on Windows and Linux (the exception is caught fine), on MacOS I get the following: terminate called after throwing an instance of 'boost::filesystem::basic_filesystem_error<boost::filesystem::basic_path<std::string, boost::filesystem::path_traits> >' what(): boost::filesystem::basic_directory_iterator constructor Abort trap The program runs fine (withouth the trap) if I comment out the upper lines. I use the boost 1.34.0 lib built as universal binary on MacOS 10.5, according to the instructions at http://svn.boost.org/trac/boost/wiki/CMakeConfigAndBuild I link to the static non-debug mt version of boost_filesystem. Exceptions within my program are caught fine, just this boost exception is not caught. The program is also compiled as non-debug. Any help would be very much appreciated. Regards, Lothar

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Boost Graph Library and Boehm Garbage Collector
by FBSL 08 Sep '08

08 Sep '08

Hello I am having trouble to garbage-collect adjacency_list<>. I have instanciated it with correctly garbage-collected vectors and lists (I have copied vecS and listS definitions, and added Boehm GC's default allocator so that they are garbage-collected). In my application I need to dynamically allocate many graphs, but it does not work, there is a (big) memory leak. Unfortunately, there is no template argument in adjacency_list<> to specify Boehm GC's allocator. Does anyone have a hint ? Snippet code "main.cpp" follows, compiled with Boost Graph Library 1.32, Boehm GC 6.4 and G++ 3.3.5, with command line : $ g++ -o main main.cpp -lgc -lgccpp -- #include <boost/graph/adjacency_list.hpp> #include <gc/gc_allocator.h> #include <gc/gc_cpp.h> #include <iostream> #include <vector> #include <list> using namespace std; using namespace boost; namespace boost { struct collected_vecS {}; struct collected_listS {}; template <class ValueType> struct container_gen<collected_vecS, ValueType> { typedef vector<ValueType,gc_allocator<ValueType> > type; }; template <class ValueType> struct container_gen<collected_listS, ValueType> { typedef list<ValueType,gc_allocator<ValueType> > type; }; template <> struct parallel_edge_traits<collected_vecS> { typedef allow_parallel_edge_tag type; }; template <> struct parallel_edge_traits<collected_listS> { typedef allow_parallel_edge_tag type; }; namespace detail { template <> struct is_random_access<collected_vecS> { enum { value = true }; typedef true_type type; }; } } typedef adjacency_list<collected_vecS, collected_vecS, directedS, no_property, no_property, no_property, collected_listS> graph; int main() { // leaks... while(true){ graph * g=new (UseGC) graph; for(unsigned int i=0; i<100; ++i){ add_vertex(*g); } for(unsigned int i=0; i<100; ++i){ for(unsigned int j=0; j<100; ++j){ add_edge(i,j,*g); } } } }

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[statechart] history transitions make state-local-storage "un-cool"
by Mick Hollins 26 Jun '08

26 Jun '08

Apologies if this has been discussed before, but I couldn't find any mention of it: I am currently using the history facility of boost::fsm. I've discovered that when I re-enter a state, X, via a history transition I don't actually re-enter the same instance of X that I was in before, but instead enter a newly constructed instance of X. I just checked the UML spec regarding history transitions and it says that "Any necessary entry actions are performed", so given that boost::fsm uses constructors to represent entry actions I guess a new instance of X has to be constructed to ensure UML compliance. My actual concern is the effect this has on the "coolness" of state-local-storage (see http://boost-sandbox.sourceforge.net/libs/statechart/doc/faq.html#Whats_so_…) It seems to me that state-local-storage, which I agree is generally cool, is particularly un-cool (and bug-inducing) in the presence of history transitions. I'm not sure what a good alternative is, but just thought I'd raise the discussion. cheers, mick PS: does the history facility display the same semantics in boost::statechart? I plan to move to statechart real soon now ...

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regex lib for Windows Mobile
by Freeman Ng 07 May '08

07 May '08

I'm trying to get the regex library (Boost ver. 1.34.1) working under Visual Studio 7.0 and the Windows Mobile 6 SDK, and have run into the following problems: 1. Need to modify visualc.hpp to define BOOST_NO_STD_LOCALE and BOOST_NO_SWPRINTF. 2. WM6 runtime library doesn't have strxfrm() or wcsxfrm(). 3. regex lib makes direct calls to ansi versions of CreateFile(), LoadLibrary(), FindFirstFile(), and others (i.e. CreateFileA(), etc.) that don't exist on the WM platform. 4. w32_regex_traits.cpp has a pragma that links directly to a library that doesn't exist for WM. (user32.lib) #1 is normal and trivial, of course, but before I tackle #2 and #3 by either writing my own versions of the missing functions or modifying the regex source, and #4 by modifying the regex source (which I really hate to do, but I can't think of any other way around this one) I want to make sure I didn't miss anything. Is there some combination of #defines or project settings that should allow the library to build for VS 7 Windows Mobile? Am I about to do more work than I need to? Thanks. Freeman

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Re: [Boost-users] Applying Boost license to non boost projects
by Robert Marion 22 Apr '08

22 Apr '08

You may wish to consider applying the liberal BSD (http://www.opensource.org/licenses/bsd-license.php) or MIT (http://www.opensource.org/licenses/mit-license.php) licenses. These are both in widespread use for open source, and impose no restrictions, aside from attribution, on the user. Putting the license text at the top of all headers is not strictly necessary, but not a bad idea. Robert Marion http://www.palamida.com > I am interested in adopting the Boost Software license for an open source C++ > library (Castor: http://www.mpprogramming.com/2.html) > > [ snip ] > - Does this same guideline apply to non boost projects ? The need for stating > Boost.org there might confuse some users of non boost prj to think that the > library is supplied by Boost. > - Do all header files in my prj (which is a pure header library) need to > include this text at the top/somewhere in order to adopt the license. > > -Roshan

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[Boost.Iostreams] Building iostreams with zlib support
by Andreas Profous 17 Apr '08

17 Apr '08

Hi, I'm trying to compile the following example code on Windows XP using MS Visual Studio 2005: -- from http://www.boost.org/libs/iostreams/doc/classes/zlib.html#installation ////////////////////////////// #include <fstream> #include <iostream> #include <boost/iostreams/filtering_streambuf.hpp> #include <boost/iostreams/copy.hpp> #include <boost/iostreams/filter/zlib.hpp> int main() { using namespace std; using namespace boost::iostreams; // added this line ifstream file("hello.z", ios_base::in | ios_base::binary); filtering_streambuf<input> in; in.push(zlib_decompressor()); in.push(file); boost::iostreams::copy(in, cout); } //////////////////////////////// So I downloaded the zlib library into the directory C:\Libs\zlib123 plus a prebuilt windows binary into the directory C:\Libs\zlib123\dll32 After reading http://www.boost.org/libs/iostreams/doc/installation.html I tried to add zlib.cpp to my test project, and to add the line #define BOOST_IOSTREAMS_NO_LIB to my source file. I got a bunch of linker errors, e.g. 1>zlib.obj : error LNK2019: unresolved external symbol _crc32 referenced in function "protected: void __thiscall boost::iostreams::detail::zlib_base::after(char const * &,char * &,bool)" (?after@zlib_base@detail@iostreams@boost@@IAEXAAPBDAAPAD_N@Z) 1>C:\Dev\Test\Test\Debug\Test.exe : fatal error LNK1120: 9 unresolved externals. If I delete ' #define BOOST_IOSTREAMS_NO_LIB' I get the following error: 1>LINK : fatal error LNK1104: cannot open file 'libboost_zlib-vc80-mt-gd-1_34_1.lib' Which is a file that doesn't exist. As I understand it I have to rebuild boost.iostreams with zlib support: C:\boost\boost_1_34_1\libs\iostreams\build>bjam "-sNO_COMPRESSION=0" "-sNO_ZLIB=0" "-sZLIB_SOURCE=C:\Libs\zlib123" "-sZLIB_LIBPATH=C:\Libs\zlib123\dll32" "-sZLIB_BINARY=zlibwapi.dll" I tried this and that but to be honest I don't really know what I'm doing and it didn't work. I would like to compile a static library and link my program against it, so that the example code works. It would also be ok to link it against a .dll - I don't really care, I just want to SOMEHOW use it! :) Can somebody give me detailed instructions on how to do that? Andreas

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Xcode 3 compile issue
by Dave DeLong 17 Apr '08

17 Apr '08

Hi everyone, I'm attempting to build a project that links against the Boost library, but I keep running into this error: /Developer/SDKs/MacOSX10.5.sdk/usr/include/c++/4.0.0/i686-apple- darwin9/bits/c++locale.h:72: error: 'snprintf' is not a member of 'std' This has come up before on this list ( http://lists.boost.org/boost-users/2008/02/34157.php ), but it doesn't seem like there was an answer. How can I get rid of this? My project requires boost.... Specs: Mac OS X 10.5, Xcode 3.0, CoreDuo chipset Thanks! Dave DeLong

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Mac Xcode 3.0 Boost compile issue
by Daniel Lord 17 Apr '08

17 Apr '08

This is a specific error with Xcode 3.0 on Leopard not a generic Boost question: Something is screwy with the paths between Boost and Xcode: Xcode 3.0 needs to find the Boost includes, so I added my directory containing the top of the Boost tree (the boost_1_34_1 directory) to the User header Search paths in the build configuration for the target. No problem, everything appears to be found. However, adding that search path screws up something else: An error pops up in c++locale.h highlighting the line: const int __ret = std::snprintf(__out, __size, __fmt, __prec, __v); and claiming: "error: 'snprintf' is not a member of 'std'." What the freak? It compiles fine from the command line with g++ and using -I<same path to boost as above>. So it is some wierd interaction with Boost and Xcode paths but it make no sense to me. It's almost as if Boost is redefining something. But what? This does not occur if I don't add the Boost search paths but of course then the Boost definitions are not found. The program is a simple one from O'Reilly's C+++ Cookbook show below: #include <boost/filesystem/operations.hpp> #include <boost/filesystem/fstream.hpp> #include <iostream> using namespace boost::filesystem; int main(int argc, char** argv) { if (argc < 2) { std::cerr << "Usage: " << argv[0] << " [dir name]\n"; return(EXIT_FAILURE); } path fullPath = // Create the full, absolute path name system_complete(path(argv[1], native)); if (!exists(fullPath)) { std::cerr << "Error: the directory " << fullPath.string( ) << " does not exist.\n"; return(EXIT_FAILURE); } if (!is_directory(fullPath)) { std::cout << fullPath.string( ) << " is not a directory!\n"; return(EXIT_SUCCESS); } directory_iterator end; for (directory_iterator it(fullPath); it != end; ++it) { // Iterate through each // element in the dir, std::cout << it->leaf( ); // almost as you would if (is_directory(*it)) // an STL container std::cout << " (dir)"; std::cout << '\n'; } return(EXIT_SUCCESS); }

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