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

trouble with bind+signals
by Brendan Miller 10 Jul '06

10 Jul '06

I'm relatively new to the boost library and I'm having a problem with boost::signals and bind. I've reproduced the problem I'm hitting here. c++: typedef boost::signal <LRESULT (ISigSource &, LPCREATESTRUCT)> SigWMCreate; SigWMCreate sig; LPARAM x; boost::bind(boost::ref(sig), boost::ref(*this), _1)((LPCREATESTRUCT)(x)); The above function application generates the following warning on msvc 8/vs2005: Error 1 error C2664: '__w64 long boost::_bi::bind_t<R,F,L>::operator ()<LPCREATESTRUCT>(A1 &) const' : cannot convert parameter 1 from 'LPCREATESTRUCT' to 'LPCREATESTRUCT &' c:\documents and settings\catphive\my documents\visual studio 2005\projects\game\game\mainfrm.cpp 20 Now, this problem goes away if x is of type LPCREATESTRUCT to start with instead of another type converted to LPCREATESTRUCT within the parentheses of the function application. This seems a bit odd to me. Also, I'd like to avoid changing how the function application is performed and get to the root of the problem since in my *actual* code, the application is performed in a system macro, and I'd like to avoid changing external headers (and having to remember what I changed in case of an update to the headers) if possible. My guess is that performing the cast creates an intermediary result that I'm not allowed to take a reference of. Is this the case? Does this happen on other compilers with analogous types? Is there a way to work around this? Thanks

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[parameter] Interface questions
by Cromwell Enage 09 Jul '06

09 Jul '06

1. Will BOOST_PARAMETER_IMPL(name) expand to the name of the function that actually "owns" the main body of code? 2. Will there be a way to define a Boost.Parameterized member function outside the class definition? Or should we let the compiler decide whether or not to inline such a function? Cromwell D. Enage __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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uint_t<bits>::value where bits is a template parameter fails to compile
by Phil Endecott 07 Jul '06

07 Jul '06

Dear All, I am having trouble using the integer library. The following fails to compile: #include <boost/integer.hpp> template <int bits> void fn(void) { //typedef boost::uint_t<8>::least t; typedef boost::uint_t<bits>::least t; t var; } int main(int argc, char* argv) { fn<8>(); } With g++ 4.0.0 on Linux and Boost 1.32, I get: boost_int_test.cc: In function â€˜void fn()â€™: boost_int_test.cc:7: error: expected initializer before â€˜tâ€™ boost_int_test.cc:8: error: â€˜tâ€™ was not declared in this scope boost_int_test.cc:8: error: expected `;' before â€˜varâ€™ The problem seems to occur when I use a template parameter - "bits" in this case - as the template parameter to uint_t. If I use a constant (as in the commented-out line) it works. Is this a C++ feature, or a bug somewhere? Can anyone suggest a workaround? Thanks, Phil.

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[spirit] working with end_p
by james.jones＠firstinvestors.com 07 Jul '06

07 Jul '06

From: Neil Hunt <boost(a)thehunts.id.au> > Hello all, > > Given a simple spirit grammar (simplified from my real grammer and > untested) such as: > > file = *line; > line = sensible_line >> ending >> *comment; > sensible_line = confix_p( '\"', *c_escape_ch_p, '\"' ); > comment = !( ch_p(';') >> ( anychar_p - eol_p ) ) >> ending; > ending = *blank_p >> ( eol_p | end_p ); > > > Note: any given line can be legitimately terminated by the end of the > file or end of line > > And there can be arbitrary numbers of comment lines between sensible lines. > > However since 'comment' is terminated with 'ending', the parser ends up > in an infinite loop matching the kleene star on end_p because it returns > zero length (doesn't advance the scanner). At least I think this is the > problem. Indeed. You can fix it by adjusting your grammar thus: line = sensible_line >> (ending >> comment)* >> ending; sensible_line ... as before comment = !( ch_p(';') >> ( anychar_p - eol_p ) ); ending ... as before - James Jones Administrative Data Mgmt. Webmaster 375 Raritan Center Pkwy, Suite A Data Architect Edison, NJ 08837

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[serialization] Facets for writing and reading infinity and nan to text streams
by Johan Råde 07 Jul '06

07 Jul '06

Following a suggestion of Robert Ramey's, I have put together facets for writing and reading non-finite floating point numbers, such as infinity and nan, to text streams, in a consistent and portable way. This is useful when serializing to text archives, but should have other applications as well. I have attached a zip file. It contains three files: 1. the actual code: non_finite_num_facets.hpp 2. documentation: non_finite_num_facets_doc.txt 3. tests: non_finite_num_facets_test.cpp The code handles char and wchar_t. It handles float, double and long double. The code has been tested with VC++ 7.1 but should work with other compilers as well. Any feedback is wellcome. --Johan Råde (rade(a)maths.lth.se)

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std::find_if, boost::mem_fn and boost::not1
by Pete Hodgson 06 Jul '06

06 Jul '06

Hi All, I'm just getting into using boost and stl algorithms, and I'm getting some indecipherable compiler errors that I'd like some help understanding. Here's some sample code: <------------------------SNIP------------------------> #include <boost/shared_ptr.hpp> #include <boost/functional.hpp> #include <boost/bind.hpp> class CEgg { public: bool IsHatched() const; }; typedef std::vector< boost::shared_ptr<CEgg> > tEggsVector; //this function compiles with no problems bool SomeEggsHaveHatched() { tEggsVector basketOfEggs; tEggsVector::const_iterator it = std::find_if( basketOfEggs.begin(), basketOfEggs.end(), boost::mem_fn( &CEgg::IsHatched ) ); bool bSomeEggsHaveHatched = ( it != basketOfEggs.end() ); return bSomeEggsHaveHatched; } //this function doesn't compile, //presumably because of the boost::not1 usage bool AllEggsHaveHatched() { tEggsVector basketOfEggs; tEggsVector::iterator it = std::find_if( basketOfEggs.begin(), basketOfEggs.end(), boost::not1( boost::mem_fn( &CEgg::IsHatched ) ) ); bool bSomeEggsHaventHatched = ( it != basketOfEggs.end() ); return !bSomeEggsHaventHatched; } <------------------------SNIP------------------------> When I try and compile this in Visual C++ 2003 I get the following compile errors for AllEggsHaveHatched(): c:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\include\algorithm(64) : error C2664: 'bool boost::unary_negate<Predicate>::operator ()(const boost::call_traits<T>::param_type) const' : cannot convert parameter 1 from 'std::allocator<_Ty>::value_type' to 'const boost::call_traits<T>::param_type' with [ Predicate=boost::_mfi::cmf0<bool,CEgg>, T=boost::unary_traits<boost::_mfi::cmf0<bool,CEgg>>::argument_type ] and [ _Ty=boost::shared_ptr<CEgg> ] and [ T=boost::unary_traits<boost::_mfi::cmf0<bool,CEgg>>::argument_type ] No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called c:\WORK\4DCapture_Soln\VideoCapture\PixelinkCaptureFacade.h(46) : see reference to function template instantiation '_InIt std::find_if<std::vector<_Ty>::iterator,boost::unary_negate<Predicate>>(_InIt,_InIt,_Pr)' being compiled with [ _InIt=std::vector<boost::shared_ptr<CEgg>>::iterator, _Ty=boost::shared_ptr<CEgg>, Predicate=boost::_mfi::cmf0<bool,CEgg>, _Pr=boost::unary_negate<boost::_mfi::cmf0<bool,CEgg>> ] Any idea why boost::not1 seems to be causing problems? Should I be using std::not1? or boost::mem_fun instead of boost:mem_fn? Cheers and TIA, Pete

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Boost compile fails on Visual C++ 6, warnings on VS8
by Sagnes, Frederic 06 Jul '06

06 Jul '06

Hello, I'm using the Boost libraries for my project (archive, threads, program_options, date_time) and these are really helpful, saved me a lot of time and the great designs make them easy to use. I'm compiling my project with Visual Studio 2005 (8.0) and gcc 4.0.1. Both work quite well, I only have warnings on VS8 because it seems to render integer operation in 64 bit and no cast is being done (a static cast would fix this), some deprecation warning which are normal, and the GCC build works well. But the VC++ 6 compilation is a real pain, here is the command line for BJam: bjam "-sTOOLS=msvc" "-sMSVC_ROOT=C:\Programme\Microsoft Visual Studio\VC98" "-sVISUALC=C:\Programme\Microsoft Visual Studio\VC98" --prefix=D:\ALM\Boost\msvc install I get a lot of compilation errors, including internal compiler errors which are quite alarming. I thought Boost libraries were meant to be portable and compile on VS6. The archive library for instance fails to build. Is there a workaround to build Boost libraries on VS6? Did I miss a switch or setting? Is VS6 that bad that it can't render complex but standard C++ code? Where can I check with which compiler Boost libraries are compatible? Best regards _______________________________________________ Frédéric Sagnes, A&D AS RD DH K3 Siemens AG Karlsruhe

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boost::bind question
by Surya Kiran Gullapalli 06 Jul '06

06 Jul '06

Hi, I've a std::map with the following structure. std::map < int, tuple<std::string, std::string> > mapTuple ; typedef map < int, tuple<string, string> > mapTuple ; Now i've say 10 elements in this container. Now i'd like to iterate thru this container and find a specific element which matches a certain criteria. Right now I'm doing this. MapIntTuple::iterator iter ; for (iter = mymap.begin(); iter != mymap.end(); ++iter) { if (iter->second.get<0>() == current_field) break ; } I'd like to iterate thru the container and find the element whose first string in the tuple matches with my search string. How can i do this using boost::lamdba::bind and std::find_if. May be that will help me in understanding boost::bind better. iter = find_if (mymap.begin(), mymap.end(), ???) ; Thanks in advance, Surya

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[date_time] unused parameter warnings with gcc
by Brian Neal 05 Jul '06

05 Jul '06

Just a suggestion: We like to compile with lots of warning turned on and try to strive for warning free builds. Under gcc, with the -Wall -W options, we get a lot of "warning: unused parameter" warnings with the date_time library. For example, /usr/include/boost-1_33/boost/date_time/time_facet.hpp:202: warning: unused parameter 'a_ref' It looks like a lot of these could be fixed by /* commenting out */ the unused parameter names; e.g. explicit time_facet(::size_t /* a_ref */ = 0) ... Thanks.

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Re: [Boost-users] [boost] [Announce] Boost Installer for Visual C++ 7.1/8.0
by Trent Nelson 05 Jul '06

05 Jul '06

> Boost Consulting is pleased to announce the availability of a Windows > installer for the current Boost release (1.33.1). See: > > http://www.boost-consulting.com/download.html Any plans to make the .nsi file you're using public? There may be a few of us out there that have experience with Nullsoft and could contribute to the installer in some way, shape or form. Trent.

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