January 2010 - Boost-users - lists.preview.boost.org

[boost::function] Is there a way to assign a generic function, regardless number of parameters?
by Matheus Araújo Aguiar 29 Jan '10

29 Jan '10

Hello list, My doubt is simple. We need to implement some callbacks, but we don't want to declare a boost::function to every different callback, we just want to declare one generic boost::function to receive any function, with any number of parameters (the return type may be one well defined, no problem with that in our case). Is there a way to do this? What we want to do is something like is done in the asynchronous methods of boost::asio when passing the callback to the async operation. TIA, -- Matheus Araújo Aguiar Computer Scientist matheus.pit(a)gmail.com

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[UTF] Provide a custom init_unit_test
by Ahmed Badran 29 Jan '10

29 Jan '10

Hi, I have a single test module (defined via BOOST_TEST_MODULE), then multiple test suites, each defined in its own .cpp file and I am using a single header variant of the unit test framework. Is there an easy way to provide my own init_unit_test and have it plug into the rest of the system, with main and everything else provided by the utf library? I've looked at the headers of utf and it seemed that the generation of main and other initialization routines are tied to also providing an "init_unit_test" which causes a multiple definition problem at link stage. Regards, Ahmed

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Operator overloading of a class template in a namespace
by Surya Kiran Gullapalli 29 Jan '10

29 Jan '10

Hello all, Let me give you a heads up first. This is a general c++ question. not a boost one. But posting it here as we've C++ gurus out there. I've this piece of code http://paste.pocoo.org/show/171324/ The code fails to compile when *St.1 *is uncommented. I read some documents on operator overloading and namespaces and moved the output operator into the same namespace as the class (skg). This works fine. But my question is different. If the output operator is in global namespace and class in skg namespace *St. 2 * (cout statement) works fine, but not the copy statement. Why ? Thanks in advance, and apologies for offtopic. Surya

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Re: [Boost-users] [multi_array] compiling and changing an example
by Steven Watanabe 29 Jan '10

29 Jan '10

AMDG sean farrow wrote: > I'm trying to use boost::multi_array, I've included boost/multi_array.hpp > in the file and have the following code: > > private: > > typedef boost::multi_array<double, 3> array_type; > > typedef array_type::index index; > > array_type test(boost::extents[3][4][2]); > > Commenting out the third line compiles fine, but leaving this in gives a > c2061 error. It seems there is an issue with boost::extents, which header > is this in? I don't have a using boost; earlier, should I have? I'm using > visual c+ 2008. > It compiles fine for me with the trunk: #include <boost/multi_array.hpp> int main() { typedef boost::multi_array<double, 3> array_type; typedef array_type::index index; array_type test(boost::extents[3][4][2]); } What version of boost are you using? What is your code exactly (with #includes)? What is the exact error message? In Christ, Steven Watanabe

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The Boost difference b/w 32 and 64 bits
by JongKwan Kim 29 Jan '10

29 Jan '10

Hello, I am running my own C and C++ code using the Boost Library. First, I run the my code with Boost Library 1.36.0 on the 32 bits linux (Ubuntu) computer, so it is working well. However, I need to move the same code on the 64 bits linux (RedHat) computer. So, I am trying to run the code with Boost Library 1.41.0 on the 64 bits linux machine. At that time, the compiling is well, but when I run it, there is segmentation fault. I do not know if the problem is because of the difference between 32 bits and 64 bits or between 1.36.0 and 1.41.0 versions. Could you guys please let me know what is problem? When I type "make install" on the prompt window, I got messages like below.... ............................. /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libz.a(crc32.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(s_atan.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(s_cos.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(s_sin.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(w_exp.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(w_fmod.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(w_log.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(w_log10.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(w_pow.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(w_sqrt.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(s_round.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(m_isnan.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(m_finite.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(s_ceilf.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(s_cosf.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(s_floorf.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(s_sinf.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(w_expf.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(w_fmodf.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(w_logf.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(w_log10f.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(w_powf.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(w_sqrtf.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(s_roundf.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(m_isnanf.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(m_finitef.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(k_standard.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(s_lib_version.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(s_matherr.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(e_exp.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(e_fmod.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(e_log.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(e_log10.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(e_pow.o)' is incompatible with i386:x86-64 output /usr/bin/ld: warning: i386 architecture of input file `/usr/lib/libm.a(s_rint.o)' is incompatible with i386:x86-64 output ...............etc............. Thanks,

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[Boost Circular Buffer] Warning C4099 when compiling with boost/circular_buffer.hpp
by Lloyd Zslnka 28 Jan '10

28 Jan '10

Boost Version: 1.35.0 Compiler: Visual Studio 2008 Version 9.0.30729.1 SP OS: Windows XP SP3 Hello, I'm compiling boost/circular_buffer.hpp with my project and am getting the following warning message: ...\boost\boost_1_35_0\boost\circular_buffer\base.hpp(180) : warning C4099: 'boost::cb_details::iterator' : type name first seen using 'class' now seen using 'struct' ...\boost\boost_1_35_0\boost\circular_buffer\details.hpp(187) : see declaration of 'boost::cb_details::iterator' ...\boost\boost_1_35_0\boost\circular_buffer\base.hpp(2477) : see reference to class template instantiation 'boost::circular_buffer<T,Alloc>' being compiled In looking at details.hpp, I see that iterator is declared as a class on line 187, but in base.hpp it is declared as a struct on line 180. Is this a mistake or am I missing something? Thanks, Lloyd --------------------------------------------------------------------- This transmission (including any attachments) may contain confidential information, privileged material (including material protected by the solicitor-client or other applicable privileges), or constitute non-public information. Any use of this information by anyone other than the intended recipient is prohibited. If you have received this transmission in error, please immediately reply to the sender and delete this information from your system. Use, dissemination, distribution, or reproduction of this transmission by unintended recipients is not authorized and may be unlawful.

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Boost, bjam, and symbolic links
by svdbg＠free.fr 28 Jan '10

28 Jan '10

Hello, I generated some Boost librairies with bjam, and I get many symbolic links. For date_time : libboost_date_time-gcc41-mt-1_39.a libboost_date_time-gcc41-mt-1_39.so -> libboost_date_time-gcc41-mt-1_39.so.1.39.0 libboost_date_time-gcc41-mt-1_39.so.1.39.0 libboost_date_time-gcc41-mt.a -> libboost_date_time-gcc41-mt-1_39.a libboost_date_time-gcc41-mt.so -> libboost_date_time-gcc41-mt-1_39.so.1.39.0 Why don't I just get the .a and .so ? Why these 3 symbolic links ? And why do the original files have a so complicated name for the .so, with the release version mentionned twice ? Isn't it possible to just have : libboost_date_time-gcc41-mt-1_39.a libboost_date_time-gcc41-mt-1_39.so Thanks for help. I don't know what to do of these symbolic links. Note : I am a newbie in Linux.

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[Boost.Thread]
by Andrew Chinkoff 28 Jan '10

28 Jan '10

Hi. There is a test program I would to be explained to me: *** BEGIN OF TEST PROGRAM *** #include <stdio.h> #include <boost/thread.hpp> #define USE_SPINLOCKS //#define USE_MUTEXES boost::thread th1; boost::thread th2; boost::mutex mutex; int global_int = 0; bool IsNotEven(int code) { boost::mutex::scoped_lock locker(mutex); bool ret = (code & 1); return ret; } void thread_func() { for(int i = 0; i < 1000000; ++i) { #ifdef USE_MUTEXES if(IsNotEven(global_int)) // (1) #elif defined USE_SPINLOCKS if(__sync_fetch_and_and(&global_int, 1)) // (2) #else ERROR__WRONG_COMPILED; #endif global_int+=9; else global_int+=1; } } int main() { th1 = boost::thread(&thread_func); th2 = boost::thread(&thread_func); th1.join(); th2.join(); printf("global_int = %d\n", global_int); return 0; } *** END OF TEST PROGRAM *** Results of test program: 1) Test program compiled with USE_SPINLOCKS. Outputs are always: "global_int = 10" "global_int = 10" "global_int = 10" 2) Test program compiled with USE_MUTEXES. Outputs differ from each other: "global_int = 10000008" "global_int = 10000000" "global_int = 9763210" Could you explain me why outputs produced with USE_SPINLOCKS compilation differ from USE_MUTEXES ones? And what is the difference between (1) and (2) lines? Best, Andrew. P.S.: I use guest Ubuntu-8.04 installed on VirtualBox. Host OS = Vista.

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Problem compiling boost libraries
by Daniel Veneros 28 Jan '10

28 Jan '10

Hi, I´m trying to compile a simple example in NetBeans 6.8 on Solaris platform, the code is: struct shm_remove { shm_remove() { shared_memory_object::remove("MySharedMemory"); } ~shm_remove(){ shared_memory_object::remove("MySharedMemory"); } } remover; //Create a shared memory object. shared_memory_object shm (create_only, "MySharedMemory", read_write); //Set size shm.truncate(1000); //Map the whole shared memory in this process mapped_region region(shm, read_write); //Write all the memory to 1 std::memset(region.get_address(), 1, region.get_size()); //Launch child process std::string s(argv[0]); s += " child "; if(0 != std::system(s.c_str())) return 1; That's it, no big deal, but when I try to build this I receive the error: Undefinded first referenced symbol in file shm_unlink, sched_yield, shm_open Anyone knows how can I fix this?? Thanks!!! Dann

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Program options support for wide char
by Bo Jensen 28 Jan '10

28 Jan '10

Program options::options_description has a output operator for std::ostream, but none for std::wostream (if I am mistaken, please correct me). Shouldn't there be one ? I could surely need one :-) Regards Bo

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[asio] Detecting tcp peer disconnection
by Igor R 28 Jan '10

28 Jan '10

Hello, This issue has previously been discussed in details, and IIRC, the conclusion was that the reliable method to detect peer disconnection is to try reading from the socket. Now I encountered strange situation: I connect tcp socket to some proprietry server, then pull out the ethernet cable from the server side. If async_read_some was in progress - nothing happens, no handler is called. If I start an additional async_read_some - nothing happens. I tried to set SO_KEEPALIVE option and waited - nothing happened. My machine runs WinXPSP3, so async_read_some is delegated to WSARecv(). I'd appreciate any idea on the subj. Thanks.

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[boost-build] boost projects, like boost/python/boost_python
by Simon Pickles 28 Jan '10

28 Jan '10

Hello, Can anyone tell me how I find which jamfile is run when the line: <library>boost/python/boost_python is encountered by bjam? And are there equivalent 'shortcuts' to other boost libraries, particularly boost unit test framework? Many thanks Si

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[String Algo] error in ireplace_first or ireplace_all with std::wstring under gcc 3.4.2 (MingW)
by Doug Swanson 28 Jan '10

28 Jan '10

I hope this is the appropriate place to post -- I apologize in advance if it is not! The following code compiles and runs without error under g++ in Windows, GCC 3.4.2 (MingW): <code> #include <cstdio> #include <string> #include <boost/algorithm/string.hpp> using namespace std; using namespace boost; int main( void ) { string test = "This is a test"; ireplace_first( test, "test", "success" ); printf( "%s\r\n", test.c_str() ); return 0; } </code> The output is correct: "This is a success". If I change the above code to use a std::wstring instead, it will compile, but it will crash on execution: <code> #include <cstdio> #include <string> #include <boost/algorithm/string.hpp> using namespace std; using namespace boost; int main( void ) { wstring test = L"This is a test"; ireplace_first( test, L"test", L"success" ); printf( "%ws\r\n", test.c_str() ); return 0; } </code> Setting a breakpoint on std::terminate() in gdb gives the following backtrace: Breakpoint 1, 0x00407ae6 in std::terminate() () (gdb) bt #0 0x00407ae6 in std::terminate() () #1 0x00404dc2 in __cxa_throw () #2 0x004021d2 in std::__throw_bad_cast() () #3 0x00434c69 in std::ctype<wchar_t> const& std::use_facet<std::ctype<wchar_t> >(std::locale const&) (__loc=@0x22fe8c) at C:/Applications/Dev-Cpp/bin/../lib/gcc/mingw32/3.4.2/../../../../include/c++/3.4.2/bits/locale_facets.tcc:112 #4 0x0043415c in wchar_t std::toupper<wchar_t>(wchar_t, std::locale const&) ( __c=84, __loc=@0x22fe8c) at C:/Applications/Dev-Cpp/bin/../lib/gcc/mingw32/3.4.2/../../../../include/c++/3.4.2/bits/locale_facets.h:4553 #5 0x0041648c in bool boost::algorithm::is_iequal::operator()<wchar_t, wchar_t> (wchar_t const&, wchar_t const&) const (this=0x22fe8c, Arg1=@0x3e3df4, Arg2=@0x43702e) at C:/Applications/Boost_new/boost/algorithm/string/compare.hpp:71 #6 0x004163fb in boost::iterator_range<__gnu_cxx::__normal_iterator<wchar_t*, std::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> > > > boost::algorithm::detail::first_finderF<wchar_t const*, boost::algorithm::is_iequal>::operator()<__gnu_cxx::__normal_iterator<wchar_t*, std::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> > > >(__gnu_cxx::__normal_iterator<wchar_t*, std::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> > >, __gnu_cxx::__normal_iterator<wchar_t*, std::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> > >) const (this=0x22fe80, Begin={_M_current = 0x3e3df4}, End={_M_current = 0x3e3e10}) at C:/Applications/Boost_new/boost/algorithm/string/detail/finder.hpp:76 #7 0x00413fe8 in void boost::algorithm::find_format<std::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >, boost::algorithm::detail::first_finderF<wchar_t const*, boost::algorithm::is_iequal>, boost::algorithm::detail::const_formatF<boost::iterator_range<wchar_t const*> > >(std::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >&, boost::algorithm::detail::first_finderF<wchar_t const*, boost::algorithm::is_iequal>, boost::algorithm::detail::const_formatF<boost::iterator_range<wchar_t const*> >) ( Input=@0x22ff50, Finder=@0x22fe80, Formatter={m_Format = {m_Begin = 0x43701e, m_End = 0x43702e, singular = false}}) at C:/Applications/Boost_new/boost/algorithm/string/find_format.hpp:146 #8 0x004141b5 in void boost::algorithm::ireplace_first<std::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >, wchar_t[5], wchar_t[8]> (std::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >&, wchar_t[5] const&, wchar_t[8] const&, std::locale const&) (Input=@0x22ff50, Search=@0x43702e, Format=@0x43701e, Loc=@0x22ff40) at C:/Applications/Boost_new/boost/algorithm/string/replace.hpp:259 #9 0x004014e8 in main () at test.cpp:11 I am not competent enough with Boost to understand what the call stack is telling me, except that __throw_bad_cast( ) is the source of the crash. ireplace_all gives the same behavior as ireplace_first above. Furthermore, the problem does not arise if I use replace_first or replace_all instead of ireplace_first or ireplace_all. It compiles and runs correctly. Finally, the problem does not arise if I compile using MSVC 2008. It compiles and runs correctly. Does this indicate a problem with gcc (MingW) unicode support? Is there an easy way to circumvent it? Thank you very much for any suggestions!

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Re: [Boost-users] [date_time][serialization] Fast persistence ofboost::date_time::ptime
by pete＠pcbartlett.com 28 Jan '10

28 Jan '10

On Thu 28/01/10 13:20 , Jeff Garland <azswdude(a)gmail.com> wrote: > Igor R wrote: > >> However on this glance this doesn’t seem possible > non-intrusively. Perhaps > >> I’ve missed something, perhaps there’s a third way > – I would be grateful if > >> any could share any ideas. > > > > Yes, it was already discussed here: > > > http://groups.google.com/group/boost-list/browse_thread/thread/d799ca831185 > 01e4/04b184b4c7af8c0b?show_docid=04b184b4c7af8c0b> > > I believe nothing changed since then. > There's not a direct way to get at the internal representation of a > ptime, > which varies based on how the library is compiled (64 or 96 bits > depending on > settings -- the thread above isn't completely accurate on this > point). If > it's critically important, of course, you could modify the source > directly to > fit your particular setup and provide the internal representation > for your app > to serialize (add a to_int64 for example). As a general rule, > however, it's > unwise to store these values as integers since future versions of > the library > might, for example, expand the epoch range and hence these > serialized values > wouldn't be compatible -- that, and the aforementioned fact that the > internal > size isn't fixed are a couple of the reasons there isn't direct > access. > Jeff Thank you both for your helpful replies (and for the helpful library!) They are good reasons. The Boost.Serialization library has it versioning mechanisms so it would be possible for a more intrusive set of load/save functions to be future- and config-proof as well as being fast. However whilst that would suit me, it has its costs - I am sure many like the readability of the current archives and I am sure the maintainer likes that the serialization functions only need to use public members of the date_time classes!

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bjam --address-model=64 doesn't work anymore?
by Daher 28 Jan '10

28 Jan '10

Using msvc100 building with: bjam --address-model=64 and unable to link output libs in my project. msvc saying its X86 and not X64 am i missing something?

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C++ and quality of software
by Peter Foelsche 28 Jan '10

28 Jan '10

I was thinking. There should be some C++ software quality assurance institution. They would give a stamp of approval to software written in C++. Criteria would be: a.. no usage fixed-sized buffers b.. no usage of functions from the c library, which do not check for correct type, like *printf(), *scanf(). c.. no dangling resources, no resource leaks in any case d.. usage of C++ Exception Handling for reporting errors (all fallible OS-calls are wrapped into C++, this can be checked by denying read/write permissions on some object, the software is trying to read/write to) e.. clean design -- e.g. no protocols (no protocols is my way of saying, that all methods of classes can be used and make sense to be used, as soon as this object exists) What do you think? I also published this on my blog: http://foelsche.spaces.live.com/blog/cns!2BFA22F3AB9E833!921.entry

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[date_time][serialization] Fast persistence of boost::date_time::ptime
by Pete Bartlett 28 Jan '10

28 Jan '10

I am interested in serializing data structures like vector< pair< boost::date_time::ptime , double> > as quickly as possible. I see that ptime is a serializable object (in the Boost.Serialization sense) but on the surface this implementation looks slow - we first get a date and time_duration and then serialize the various components (mins,secs,subsecs) separately for the latter and construct a full ISO string for the date. Something faster is surely possible - digging into the implementation it looks like a (non-special) ptime is represented as boost::uint64_t so if we were privy to all implementation details we could use serialize that. However on this glance this doesn't seem possible non-intrusively. Perhaps I've missed something, perhaps there's a third way - I would be grateful if any could share any ideas. Thanks, Pete

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passing socket descriptor to a function
by pedro chaparro 28 Jan '10

28 Jan '10

Hi, i have the code below, i want to separate the open socket code from the writting fucntions, i want to call a escribir() function from the main but i¡m not clear the value i have to pass the function, inthe way i have below it has not work. thanks #include <ctime> #include <iostream> #include <string> #include <boost/asio.hpp> using boost::asio::ip::tcp; void escribir( tcp::socket socket){ std::string message = "mensaje"; boost::system::error_code ignored_error; boost::asio::write(socket, boost::asio::buffer(message), boost::asio::transfer_all(), ignored_error); } int main() { int contador=0; try { boost::asio::io_service io_service; tcp::acceptor acceptor(io_service, tcp::endpoint(tcp::v4(), 5544)); for (;;) { tcp::socket socket(io_service); acceptor.accept(socket); escribir(socket); } } catch (std::exception& e) { std::cerr << e.what() << std::endl; } return 0; } -- Ing Pedro Alonso Chaparro Valero Ciudad Politecnica de la Innovación iTEAM - Mobile Communications Group Polytechnic University of Valencia C\ Camino de Vera S/N, Edificio 8G 46022 Valencia, Spain

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Re: [Boost-users] [interprocess] shared_memory_object constructor with create_only parameter
by Philipp Hamann 28 Jan '10

28 Jan '10

Hi all, I am sorry. I made a mistake. My first problem is solved. It is not a bug. > I have some problems using the shared_memory_object constructor with the > create_only parameter. > The goal is to allow only one process to write to the shared memory. So > I create a shared_memory_object with the create_only parameter. For the > first process this is successful (as I assumed), but for the second > process (same parameters) this is successful, too (not as I assumed). > The documentation of boost says that it should throw an exception, if > the shared memory is allready created. Is this a bug or a misuse or > understanding of the library? But the second problem concerning shared_memory_object::remove(const char* name) is still present. > I realized another problem. If I call the static function > shared_memory_object::remove(const char* name), the memory should be > removed only when no further process has access to the memory. This > seems also not to work. I did the following: > 1. create shared memory for writing. > 2. open shared memory for reading > 3. shared_memory_object::remove(const char* name) (from the reading > process) > 4. reopen the shared memory for reading -> exception: can not find the file Thanks for your help and apoligizes for bothering you with my first problem. Philipp

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serialization: pointer reconstruction
by Noah Roberts 27 Jan '10

27 Jan '10

A while back I asked about saving a pointer to an item in another class that is stored as a direct instance variable (no pointer). Here's a brief illustration: struct A { }; struct B { A a; }; struct C { A * a; // points to a B::a. }; I have an idea how to store and restore these relationships but I'd like to see if there are any improvement ideas and/or direction to existing behavior I'm not seeing in the documentation. My idea is to first store B::a (which simply makes sense in my problem anyway) and when I do this to call some custom support functions to generate a unique ID for the object at that address and store it first, then the rest of the data in A. This would appear in A::serialize and the unique ID would be stored in the Archive (added behavior) as a map from address to uid. Then when storing C I would request the unique ID for the address the pointer stores and store it. On reading I read B::a first and it sort of reverses the process. The uid is read and then A::serialize stores the uid and 'this' in the archive map in a uid->address format. I then read the uid on reading C::a and request the address from the archive using that value. I've already subclassed the Archive in order to pass around other load information needed by classes that didn't have local copies, so that's the easy part (though it wasn't a straight forward operation). The question I have though is that since the pointer archiving already must use some similar type of API, can I use it instead of rolling my own and how would I do that?

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Issues with unnamed enums
by Kyle Altendorf 27 Jan '10

27 Jan '10

I have just tried to use Boost for the first time and it appears to not take kindly to unnamed enums from another library I use and (once those were named) some Microsoft SDK. I am using: Windows XP SP3 Visual Studio 2008 SP1 Boost 1.41.0 More specifically, after adding '#include <boost/foreach.hpp>' I started getting compilation errors such as: 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : error C2332: 'class' : missing tag name 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : error C2011: '<unnamed-tag>' : 'enum' type redefinition 1> c:\korvis\korvislibs\khmilib\kvdisplay.h(18) : see declaration of '<unnamed-tag>' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : error C2143: syntax error : missing ',' before 'constant' kvdisplay.h(18) is the definition of an unnamed enum in another library I use. iterator_facade.hpp(43) is (including comments before it): > // This forward declaration is required for the friend declaration > // in iterator_core_access > template <class I, class V, class TC, class R, class D> class iterator_facade; I went through and named a each of the unnamed enums as the compiler referenced them until I got to an issue with shlwapi.h from a Microsoft SDK. Here's the complete compiler error list at that point: 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : error C2332: 'class' : missing tag name 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : error C2011: '<unnamed-tag>' : 'enum' type redefinition 1> c:\program files\microsoft sdks\windows\v6.0a\include\shlwapi.h(1550) : see declaration of '<unnamed-tag>' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : error C2143: syntax error : missing ',' before 'constant' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(479) : error C2332: 'class' : missing tag name 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(479) : error C2011: '<unnamed-tag>' : 'enum' type redefinition 1> c:\program files\microsoft sdks\windows\v6.0a\include\shlwapi.h(1550) : see declaration of '<unnamed-tag>' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(479) : error C2143: syntax error : missing ',' before 'constant' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(484) : error C2977: 'boost::iterator_facade' : too many template arguments 1> c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : see declaration of 'boost::iterator_facade' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(484) : error C2977: 'boost::iterator_facade' : too many template arguments 1> c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : see declaration of 'boost::iterator_facade' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(485) : error C2977: 'boost::iterator_facade' : too many template arguments 1> c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : see declaration of 'boost::iterator_facade' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(485) : error C2977: 'boost::iterator_facade' : too many template arguments 1> c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : see declaration of 'boost::iterator_facade' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(487) : error C2977: 'boost::iterator_facade' : too many template arguments 1> c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : see declaration of 'boost::iterator_facade' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(487) : error C2977: 'boost::iterator_facade' : too many template arguments 1> c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : see declaration of 'boost::iterator_facade' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(488) : error C2977: 'boost::iterator_facade' : too many template arguments 1> c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : see declaration of 'boost::iterator_facade' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(488) : error C2977: 'boost::iterator_facade' : too many template arguments 1> c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : see declaration of 'boost::iterator_facade' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(489) : error C2977: 'boost::iterator_facade' : too many template arguments 1> c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : see declaration of 'boost::iterator_facade' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(489) : error C2977: 'boost::iterator_facade' : too many template arguments 1> c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : see declaration of 'boost::iterator_facade' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(490) : error C2977: 'boost::iterator_facade' : too many template arguments 1> c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : see declaration of 'boost::iterator_facade' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(490) : error C2977: 'boost::iterator_facade' : too many template arguments 1> c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : see declaration of 'boost::iterator_facade' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(494) : error C2977: 'boost::iterator_facade' : too many template arguments 1> c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : see declaration of 'boost::iterator_facade' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(494) : error C2977: 'boost::iterator_facade' : too many template arguments 1> c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : see declaration of 'boost::iterator_facade' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(501) : error C2977: 'boost::iterator_facade' : too many template arguments 1> c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : see declaration of 'boost::iterator_facade' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(508) : error C2977: 'boost::iterator_facade' : too many template arguments 1> c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(43) : see declaration of 'boost::iterator_facade' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(566) : error C2332: 'class' : missing tag name 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(566) : error C2011: '<unnamed-tag>' : 'enum' type redefinition 1> c:\program files\microsoft sdks\windows\v6.0a\include\shlwapi.h(1550) : see declaration of '<unnamed-tag>' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(566) : error C2143: syntax error : missing ',' before 'constant' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(567) : error C2988: unrecognizable template declaration/definition 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(567) : error C2059: syntax error : 'constant' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(567) : error C2065: 'V' : undeclared identifier 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(567) : error C2065: 'TC' : undeclared identifier 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(567) : error C2065: 'R' : undeclared identifier 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(567) : error C2065: 'D' : undeclared identifier 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(572) : error C2332: 'class' : missing tag name 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(572) : error C2011: '<unnamed-tag>' : 'enum' type redefinition 1> c:\program files\microsoft sdks\windows\v6.0a\include\shlwapi.h(1550) : see declaration of '<unnamed-tag>' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(573) : error C2065: 'V' : undeclared identifier 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(573) : error C2065: 'TC' : undeclared identifier 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(573) : error C2065: 'R' : undeclared identifier 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(573) : error C2065: 'D' : undeclared identifier 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(574) : error C2334: unexpected token(s) preceding '{'; skipping apparent function body 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(721) : error C3855: 'boost::iterator_facade': template parameter '__formal' is incompatible with the declaration 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(721) : error C2977: 'boost::iterator_facade' : too many template arguments 1> c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(601) : see declaration of 'boost::iterator_facade' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(724) : error C2332: 'class' : missing tag name 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(724) : error C2011: '<unnamed-tag>' : 'enum' type redefinition 1> c:\program files\microsoft sdks\windows\v6.0a\include\shlwapi.h(1550) : see declaration of '<unnamed-tag>' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(724) : error C2143: syntax error : missing ',' before 'constant' 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(725) : error C2065: 'V' : undeclared identifier 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(725) : error C2065: 'R' : undeclared identifier 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(725) : error C2065: 'TC' : undeclared identifier 1>c:\korvis\boost\include\boost\iterator\iterator_facade.hpp(726) : fatal error C1903: unable to recover from previous error(s); stopping compilation Am I correct that the unnamed enums are somehow causing the problem? Any help you can offer understanding or resolving this issue would be greatly appreciated. Thanks for your time, -kyle

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Query re connected components in the Boost Graph Library
by Christopher Henrich 27 Jan '10

27 Jan '10

The connected_components function in the BGL returns the connected component information in a "ComponentMap," in which the value for node i is the number c[i] of the component containing that node. Is the sequence of component numbers "restricted growth" ? That is, can I assume that c[0] = 0 and for i > 0, c[i] <= 1 + max(c[0], ..., c[i-1])? It would appear that this would be true, as a consequence of the easiest way to use depth-first search to find the components. And a brief attempt to read the source code encourages me to believe it. But I may not have understood the source code. And I do not find it stated in the boost documentation, nor in /The Boost Graph Library/. Thanks in advance for clarification on this point. Christopher Henrich chenrich(a)monmouth.com mathinteract.com

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[thread] Is a call to interrupt_all blocking?
by Sachin Garg 27 Jan '10

27 Jan '10

Does a call to interrupt_all blocks the calling thread, waiting for all threads to be interrupted? Or is it supposed to return immediately and let the threads hit their interruption points later? I have a thread_group and I want to call interrupt_all to stop all threads in the group from 'within' one of the threads in that group. This would be possible only if interrupt_all in not blocking, otherwise I will need to somehow signal some other thread to do the interrupt_all on that group. SG

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Question on grammar
by Manjunath Kudlur 27 Jan '10

27 Jan '10

I am sure this has been asked before, but I am not able to find an answer to my specific question in the archives. I wanted to create a grammar that can accept statements like if_(expr)[ statement-list ].else_[statement-list]. I created a if_expr type using proto::extends, and added a member called else_ to it, of type proto::function<proto::terminal<if_then_else>, Expr const&>. The code is given below. I am trying to match statements of the above form. Look for if_only_grammar and if_grammar below. The main function has 2 cases, one with just if_ and another with if_ and else_. My grammar matches neither of them. What am I doing wrong? I am quite the newbie to proto, so I am not still able to parse the compiler error message and understand it yet. I will be grateful for any help. Thanks, Manjunath #include <boost/proto/proto.hpp> #include <boost/mpl/bool.hpp> #include <boost/mpl/assert.hpp> #include <iostream> #include <sstream> #include <string> using namespace boost; using namespace std; unsigned int ids; template<typename VT> struct Var { unsigned int id; Var() { id = ++ids; } }; struct if_fun {}; struct program {}; struct if_then_else {}; struct if_domain; template <typename Expr> struct if_expr : proto::extends<Expr, if_expr<Expr>, if_domain> { typedef proto::extends<Expr, if_expr<Expr>, if_domain> base_type; using base_type::operator =; typedef typename proto::result_of::make_expr<proto::tag::function, if_then_else, Expr const &>::type else_type; else_type else_; if_expr(Expr const &e = Expr()) : base_type(e) , else_(proto::make_expr<proto::tag::function>(if_then_else(), boost::ref(e))) {} }; struct if_domain : proto::domain<proto::generator<if_expr> > { }; struct napl_grammar; struct arith_expr_grammar; struct rel_expr_grammar; struct assign_grammar; struct statement_grammar; struct bb_grammar; struct if_only_grammar : proto::or_< proto::subscript<proto::function<if_expr<proto::terminal<if_fun>::type>, rel_expr_grammar >, bb_grammar> > { }; struct if_grammar : proto::or_< if_only_grammar, proto::subscript<proto::function<proto::terminal<if_then_else>, if_only_grammar>, bb_grammar> > { }; struct arith_expr_grammar : proto::or_< proto::plus< arith_expr_grammar, arith_expr_grammar>, proto::minus< arith_expr_grammar, arith_expr_grammar>, proto::multiplies< arith_expr_grammar, arith_expr_grammar>, proto::divides< arith_expr_grammar, arith_expr_grammar>, proto::terminal<Var<int> >, proto::terminal<int>, rel_expr_grammar > { }; struct rel_expr_grammar : proto::or_< proto::less< arith_expr_grammar, arith_expr_grammar>, proto::greater< arith_expr_grammar, arith_expr_grammar>, proto::less_equal< arith_expr_grammar, arith_expr_grammar>, proto::greater_equal< arith_expr_grammar, arith_expr_grammar>, proto::equal_to< arith_expr_grammar, arith_expr_grammar>, proto::not_equal_to< arith_expr_grammar, arith_expr_grammar>, proto::logical_not< rel_expr_grammar> > { }; struct assign_grammar : proto::or_< proto::assign<proto::terminal<Var<int> >, arith_expr_grammar>, proto::assign<proto::terminal<Var<int> >, rel_expr_grammar> > { }; struct statement_grammar : proto::or_< assign_grammar, if_grammar > { }; struct bb_grammar : proto::or_< statement_grammar, proto::comma<bb_grammar, statement_grammar> > { }; struct napl_grammar : proto::or_< proto::terminal<program>, proto::subscript<proto::terminal<program>, bb_grammar> > { }; template<typename Expr> void check_and_execute(const Expr &e, mpl::true_) { cout << "Program printer TBD.\n"; } template<typename Expr> void check_and_execute(const Expr &e, mpl::false_) { cout << "Should not be here\n"; } template<typename Expr> void check_grammar(const Expr &e) { BOOST_MPL_ASSERT_MSG((proto::matches<Expr, napl_grammar>::value), SYNTAX_NOT_CORRECT, (void)); check_and_execute(e, proto::matches<Expr, napl_grammar>()); //cout << napl_grammar()(e) << "\n"; } int main() { proto::terminal<Var<int> >::type i1, i2, i3, i4, i5; proto::terminal<program>::type Program; if_expr<proto::terminal<if_fun>::type> if_; int i=4242; check_grammar( Program[ if_(i1 < i2) [ i2 ] ]); /* check_grammar( Program[ if_(i1 < i2) [ i2 ].else_[ i3 ] ]); */ }

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[multi_index] modify_key with an iterator to composite_key
by Christian Holmquist 27 Jan '10

27 Jan '10

Hi, >From what I've found on the net (here: http://groups.google.com/group/boost-list/browse_thread/thread/687ce9662a4c…) about this problem, Joaquin explains that modify_key on a composite_key isn't supported. Relevant part from that thread is: When you use modify_key, you modifier functor is passed > *the key* rather than the whole element as is the case > with modify. In this particular situation, the key is > a composite key; so the key object (defined privately > by composite_key) is some entity that somehow references > entry::m_x and entry::m_y. This object is not exposed > to the public and you're not supposed to try to use > it or modify it, hence the problems you're seeing. > In short, when using composite_key you cannot use > modify_key. The alternative must be to use modify() instead, so I'd like to know how to get the best performance in the following scenario: My index is specified as. namespace bmi = boost::multi_index; struct Index : boost::mpl::vector2 < bmi::hashed_unique<bmi::member<Entry, std::string, &Entry::m_Name> >, bmi::ordered_non_unique < bmi::composite_key < Entry, bmi::member<Entry, int, &Entry::m_State>, bmi::member<Entry, int, &Entry::m_Timestamp> > > > {}; I frequently updated Entry::m_State and Entry::m_Timestamp, but never Entry::m_Name during the lifetime of an entry, thus I expected modify_key to be faster since the expensive hash index don't need to be updated. Since I cannot tell modify() which parts of the Entry I'm about to update, I don't see how I can avoid the rehashing. Maybe there's a better way to configure the index? I'm using Entry::m_State for an equal_range() search, while Entry::m_Timestamp is only for ordering (I bump the timestamp everytime I change m_State). I am using boost.1.35 btw Any response much appreciated, Christian

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