September 2006 - Boost-users - lists.preview.boost.org

BOOST_FOREACH and maps
by Rob Caldecott 18 Sep '06

18 Sep '06

OK, I know BOOST_FOREACH isn't part of the official (1.33.1) build yet, but hopefully some people here are using this excellent algorithm and can help me out... (note that I am using MS Visual Studio 2005): How can I use BOOST_FOREACH to iterate through a map? For example, the following won't build: std::map<int, int> m; BOOST_FOREACH(std::pair<int, int> p, m) { } I get the following error: warning C4002: too many actual parameters for macro 'BOOST_FOREACH' However, the following will work OK: std::map<int, int> m; std::pair<int, int> p; BOOST_FOREACH(p, m) { } But is there a way to declare the pair within the FOREACH loop? Note that I also tried the following, with no success: std::map<int, int> m; BOOST_FOREACH(std::map<int, int>::value_type p, m) { } A typedef also seems to work, e.g.: std::map<int, int> m; typedef std::pair<int, int> mpair; BOOST_FOREACH(mpair p, m) { } Can the pair be declared without a typedef? Is this a limitation of the MS compiler? Thanks in advance.

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edge function
by Tom Lenaerts 18 Sep '06

18 Sep '06

This is again a newbie question. I want to create a graph based on some input file. I parse this file and in the code I want to check whether the link already exists int current=strToInt(tokens[0]); int numedges=strToInt(tokens[1]); for(int i=0;i<numedges;i++){ Vertex first=vertex(current,*g); int other=strToInt(tokens[3+i]); Vertex second=vertex(other,*g); pair<Edge, bool> result=boost::edge(first,second,*g); if(!result.second){ boost::add_edge(first,second,*g); } } tokens[0] is the id of the node, tokens[1] contains the number of edges this node is pointing to. From tokens[3] until the end, one gets the nodes to which the current node is connected (stored in other) As you can see I call the function boost::edge() to check whether there is already a link between first and second. As soon as I do this I get an error in Xcode. Does anyone know what I'm doing wrong here. It probably something very simple but I don't see it. Thanks in advance Tom

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Boost.python iterator , range
by CT 18 Sep '06

18 Sep '06

Hi , Can someone can give me some help on how to expose correctly an array of object pointers using boost.python ? here is a small example of what i need i have a class class A { public: A(std::string &oName); ~A(){} const std::string &GetName() const; } class B { std::vector<*A> *poNames public: std::vector<*A> GetNames() { return *poNames } } assume that there is two instances of A in the container of the object B now for the boost::python code. I would like to be able to expose class a and class b and the vector of A* typedef std::vector<A*> array_proj; array_proj::iterator begin_array_proj(array_proj &x) {return x.begin();} array_proj::iterator end_array_proj(array_proj &x) {return x.end();} BOOST_PYTHON_MODULE(pysession) { class_<A>("object a",init<std::string &) .def("GetName",&A::GetName,return_value_policy <copy_const_reference>() ) ; class_<B>("object B") .def("GetNames", &B::GetNames, return_value_policy<manage_new_object>() ) ; class_<std::vector<*A> >("array of pointer to objects A") .def("__iter__", range( begin_array_proj, end_array_proj) ) ; } Now in python for example I call #create a new object B #and iterate over all of the object A #assume that there are two object of type A in the vector oNewSession = pysession.B() oVector = oNewSession.GetNames() for oA in oVector.__iter__(): print (oA.GetName()) i have this error when i start the python script for oA in oVector.__iter__(): TypeError: No to_python (by-value) converter found for C++ type: class ::A * Does someone can give me some help on how to expose correctly an array of pointers using boost.python ?

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Dereferencing value for algorithm
by Alexander Shyrokov 18 Sep '06

18 Sep '06

An iterator is pointing to a pointer, how do I add another dereferencing operator in the algorithm, so it works on values? void f(int& i); vector<int*> a; // this would work if f would be void f(int* i) for_each(a.begin(),a.end(),boost::bind(f,_1)); I could define a dereferencing predicate: template<class T> struct deref{ typedef T result_type; T operator()(T* p){assert(p);return *p;} }; for_each(a.begin(),a.end(),boost::bind(f,boost::bind(deref<int>,_1))); but this requires supplying a template parameter. Is there an easier way? Thanks. -- Regards, Alexander. http://sjcomp.com

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[multi_index].[example].[composite_keys]. Fails to compile with Solaris 10
by Prashant Thakre 18 Sep '06

18 Sep '06

Hi, OS: SunOS 5.10 >>CC -V CC: Sun C++ 5.8 Patch 121017-04 2006/08/02 I am trying to compile composite_keys.cpp with Sun Studio 11. After applying all the patches listed at http://developers.sun.com/prodtech/cc/downloads/ patches/ss11_patches.html, http://blogs.sun.com/roller/resources/sga/ boost_1_33_1.patch and following instructions listed at http://blogs.sun.com/ sga/entry/boost_1_33_1, am still unable to do so. However, I can compile other examples provided with multi_index. >>CC -library=stlport4 -features=tmplife -featurestmplrefstatic -fast -I$BOOST_INCLUDE composite_keys.cpp ----------------------------------------------------------------------------- boost/include/boost-1_33_1/boost/multi_index/ordered_index.hpp", line 784: Error: boost::multi_index::composite_key_compare<std::less<const file_entry*>, std::less<std::string>, 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>::operator()<boost::multi_index:: composite_key<file_entry, boost::multi_index::member<file_entry, const file_entry*, 21>, boost::multi_index::member<file_entry, std::string, 1>, 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::multi_index::composite_key<file_entry, boost::multi_index:: member<file_entry, const file_entry*, 21>, boost::multi_index::member<file_entry, std::string, 1>, 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 boost::multi_index::composite_ key_result<boost::multi_index::composite_key<file_entry, boost::multi_index::member<file_entry, const file_entry*, 21>, boost::multi_index::member<file_entry, std::string,1>, 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 boost::multi_index::composite_key_result< boost::multi_index::composite_key<file_entry, boost::multi_index::member<file_entry, const file_entry*, 21>, boost::multi_index::member<file_entry, std::string, 1>, 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 is not accessible from boost::multi_index::detail::ordered_index<name_key, std::less<boost::multi_index::composite_key_result< boost::multi_index::composite_key<file_entry, boost::multi_index::member<file_entry, const file_entry*, 21>, boost::multi_index::member<file_entry, std::string, 1>, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::nulles::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::multi_index::detail::nth_layer<1,file_entry, boost::multi_index::indexed_by<boost::multi_index::ordered_unique<name_key, mpl_::na, mpl_::na>, boost::multi_index::ordered_non_unique< size_key, 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>, std::allocator<file_entry>> , boost::mpl::vector0<mpl_::na>, boost::multi_index::detail::ordered_unique_tag>::invariant_() const. ----------------------------------------------------------------------------- similar error is reported for line 785 ("boost/include/boost-1_33_1/boost/ multi_index/ordered_index.hpp" ) regards, Prashant Thakre

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[program options] Using similar option strings
by Jason House 18 Sep '06

18 Sep '06

I recent attempted the equivalent of allowing the follwoing two options: --help --help-command [arg] --help-component [arg] When I ran the program with --help, I got an error that it was ambiguous. I didn't realize it, but program options allows the user to not specify the full string with "--". This then makes all the options above match --help. How can I get this type of functionality without getting runtime errors about ambiguity? If I were to reduce it to just --help and --help-command, it may be possible to just do --help with an optional argument, but I don't know how to do that. Currently, I'd like to avoid a shared namespace for commands and components.

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Re: [Boost-users] Library Interface Design
by Sohail Somani 18 Sep '06

18 Sep '06

> -----Original Message----- > From: boost-users-bounces(a)lists.boost.org > [mailto:boost-users-bounces@lists.boost.org] On Behalf Of > Robert Kindred > > Can you not create them all, have them wait on some > condition variable > > and signal when you're ready to go? > > Yes, I suppose that works, with some extra effort. So does > this mean that a > monolithic constructor is very important to you? Not necessarily a monolithic constructor. Just before it starts doing work, you wait on the condition. I wouldn't expect that to be a ton of work. However, it is important to me to not have to remember the order in which to create things. This is just asking for a bug at 2am. Sohail

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boost::interprocess::node_allocator & VC8 run-time problem
by alexmark 18 Sep '06

18 Sep '06

I have the problem with VC8 release build (all release build options - by default, i.e., optimization is "Maximize speed /O2" and so on). A run of "repro" output executable finishes with the exception on attempt to read data from address 0. I noticed it for boost::interprocess (and boost::shmem too) allocators of type: - node_allocator - cached_node_allocator and not to: - allocator - private_node_allocator The way out I found (for "problematic" allocator types) is to set additional compiler option "/Og-" (already declared deprecated). With VC7.1 it all is ok for any allocator type w/o setting /Og- or any other additional options. Have anyone noticed this problem? Where the problem originates from? VC8 optimization specifics (NRVO is affected by /Og option)? Or smth. wrong in "repro" code? Thanks. ////////////// The "repro" code is the following: #include "stdafx.h" #include <boost/interprocess/managed_external_buffer.hpp> #include <boost/interprocess/allocators/node_allocator.hpp> #include <boost/interprocess/containers/list.hpp> using namespace boost::interprocess; enum { A_SHARED_MEMORY_SIZE = 65536, A_POOL_SIZE = 64 }; typedef node_allocator<int, A_POOL_SIZE, managed_external_buffer::segment_manager> user_allocator_t; typedef list<int, user_allocator_t> MyUserList; int _tmain(int argc, _TCHAR* argv[]) { static char static_buffer[A_SHARED_MEMORY_SIZE]; managed_external_buffer user_buffer(create_only, static_buffer, A_SHARED_MEMORY_SIZE); MyUserList *userlist = user_buffer.construct<MyUserList>("MyUserList")(user_buffer.get_segment_manager()); return 0; }

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Memory leask in class thread.
by 蹬三轮的 18 Sep '06

18 Sep '06

I found a memory leak in boost's thread class. Here is the sample program: void func() { } int _tmain(int argc, _TCHAR* argv[]) { _CrtSetReportMode(_CRT_WARN, _CRTDBG_MODE_DEBUG); _CrtSetReportMode(_CRT_ERROR, _CRTDBG_MODE_DEBUG); _CrtSetReportMode(_CRT_ASSERT, _CRTDBG_MODE_DEBUG); { thread t(func); t.join(); } _CrtDumpMemoryLeaks(); return 0; } The output is: The thread 'Win32 Thread' (0xb24) has exited with code 0 (0x0). Detected memory leaks! Dumping objects -> {188} normal block at 0x003A9DA8, 24 bytes long. Data: < - > D0 2D 15 00 FF FF FF FF 00 00 00 00 00 00 00 00 {187} normal block at 0x003A9C78, 8 bytes long. Data: < : > A8 9D 3A 00 01 CD CD CD Object dump complete. So I think boost should resolve this problem in the next version.

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Pb with Boost and VC++7.1 : inconsistent code ?
by Washburn 18 Sep '06

18 Sep '06

Hello everyone. I'm new to this mailing-list but I have a very annoying and urgent problem concerning Boost and the STL. I just upgraded to Boost 1.33.1 which is needed for the new version of libtorrent, linked statically in one of my DLLs. Build of Boost went quite well (using BJam) Build of lib went OK. Build of DLL : no problem either. But then at runtime I get this : Unhandled exception at 0x77e79282 in TestFileDl.exe: Microsoft C++ exception: boost::filesystem::filesystem_error @ 0x0012d654. Exception thrown in [path_posix_windows.cpp] line 339 : if ( !checker( name ) ) { boost::throw_exception( filesystem_error( "boost::filesystem::path", "invalid name \"" + name + "\" in path: \"" + src + "\"" ) ); } ... because this check does not behave properly : BOOST_FILESYSTEM_DECL bool windows_name( const std::string & name ) { return name.size() != 0 && name.find_first_of( windows_invalid_chars ) == std::string::npos <-------------- (here) && *(name.end()-1) != ' ' && (*(name.end()-1) != '.' || name.length() == 1 || name == ".."); } ... because find_first_of does not return what it should, in [xstring] : size_type find_first_of(const _Elem *_Ptr, size_type _Off, size_type _Count) const { // look for one of [_Ptr, _Ptr + _Count) at or after _Off if (0 < _Count && _Off < _Mysize) { // room for match, look for it const _Elem *const _Vptr = _Myptr() + _Mysize; for (const _Elem *_Uptr = _Myptr() + _Off; _Uptr < _Vptr; ++_Uptr) if (_Traits::find(_Ptr, _Count, *_Uptr) != 0) return (_Uptr - _Myptr()); // found a match } return (npos); // no match } Obviously the std::string is screwed up here, because I think _Mysize should not be 31, which makes the [for] searche outside the boudaries of the buffer, thus returning the wrong results... + this 0x0012d854 {"main_session.log"} const std::basic_string<char,std::char_traits<char>,std::allocator<char> > * const _Mysize 31 unsigned int I also believe that the symbol table is wrong here but I'm not sure. This piece of code belongs to the libtorrent project and is supposed to be stable. Then it gets even worse : after the acual throwing of the exception (the "throw" instruction), my call stack is screwed with a call to feeefeee()... I tried all compilation and link options, getting always the same result. Any idea people ? Please help :( Washburn

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