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boost::bind vs boost::mem_fun (was RE: [Boost-users] Re: shared_ptrs with std::mem_fn)
by Mark Storer 10 May '04

10 May '04

> > template<class _R, class _Ty> > > class mem_fun_t : public unary_function<_Ty *, _R> { > > public: > > explicit mem_fun_t(_R (_Ty::*_Pm)()) > > : _Ptr(_Pm) {} > > _R operator()(_Ty *_P) const > ^^^^^^^ > > {return ((_P->*_Ptr)()); } > > private: > > _R (_Ty::*_Ptr)(); > > }; > > --- > > <...> > No, the relevant part is the signature I highlighted above. <...> > > All I have to say is "use boost::mem_fn, which works, and never > touch the one in std::". Thanks for clearing that up, it was really bugging me. So to speak. ;) I've recently started using boost::bind, and I think I'm in love. But boost::mem_fun raises another question in my mind: Are there any cases where "boost::bind( &foo::bar, _1 )" is superior to "boost::mem_fun( &foo::bar )" (other than a few less keys to press)? I'd say that boost::bind is clearly supperior when "bar" takes a parameter, but when it does not, the water gets a little muddy. I'd imagine that you wouldn't get the long stream of error messages (expected N params not Y, expected N + 1 params, not Y, expected N + 2 ...) from bind when all the different variants miss, but is there anything else? --Mark Storer Senior Software Engineer Verity, Inc.

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RE: [Boost-users] boost 1.30 / date_time / link problem with VC7
by Ben Hutchings 10 May '04

10 May '04

Dan Dimerman <dan_dimerman(a)hotmail.com> wrote: > I'm having the following problem when linking a MSWindows MFC > application with the static library libboost_date_time.lib using > DevStudio .Net 7.0. > > The output looks like this: > > ------ Build started: Project: Main, Configuration: Debug Win32 ------ > Linking... > MSVCRTD.lib(ti_inst.obj) : error LNK2005: "private: __thiscall > type_info::type_info(class type_info const &)" > (??0type_info@@AAE@ABV0@@Z) already defined in libcmtd.lib(typinfo.obj) > MSVCRTD.lib(ti_inst.obj) : error LNK2005: "private: class type_info & > __thiscall type_info::operator=(class type_info const &)" > (??4type_info@@AAEAAV0@ABV0@@Z) already defined in > libcmtd.lib(typinfo.obj) > LINK : warning LNK4098: defaultlib 'MSVCRTD' conflicts with > use of other libs; use /NODEFAULTLIB:library > Debug/Main.exe : fatal error LNK1169: one or more multiply > defined symbols found > > I am working with the "Multi-threaded Debug (/MTd)" version of > libraries. > Tried using alternatives, but I got errors elsewhere and the > errors above persisted. > From boost, I am using the library built at "My Documents\Visual > Studio Projects\boost\libs\date_time\build\bin\libboost_date_time.lib > \vc7\debug\runtime-link-dynamic" > > Any help will be greatly appreciated... You are using the debug DLL version of the date_time library. In order to share a heap with the main program this uses the debug DLL version of the C++ run-time library (MSVCRTD) and requires that the main program uses it too. You must either: (1) Build and use the debug multi-threaded static version of the date_time library. (2) Use the debug DLL versions of the C++ run-time library and MFC in your main program.

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help: boost::thread and compile error
by Guillermo Martony 10 May '04

10 May '04

Greetings, The following code taken from an example compiles without errors: #include <boost/thread/thread.hpp> #include <boost/thread/xtime.hpp> #include <iostream> class thread_alarm { public: thread_alarm(int secs) : m_secs(secs) { } void operator()() { boost::xtime xt; boost::xtime_get(&xt, boost::TIME_UTC); xt.sec += m_secs; boost::thread::sleep(xt); std::cout << "alarm sounded..." << std::endl; } private: int m_secs; }; int main() { int secs = 5; std::cout << "setting alarm for 5 seconds..." << std::endl; thread_alarm alarm(secs); boost::thread thrd(alarm); thrd.join(); return 0; } But adding a std::fstream varible to the thread_alarm class: #include <fstream> #include <boost/thread/thread.hpp> #include <boost/thread/xtime.hpp> #include <iostream> class thread_alarm { public: thread_alarm(int secs) : m_secs(secs) { } void operator()() { boost::xtime xt; boost::xtime_get(&xt, boost::TIME_UTC); xt.sec += m_secs; boost::thread::sleep(xt); std::cout << "alarm sounded..." << std::endl; } private: int m_secs; std::fstream fs; // only this line was added }; int main() { int secs = 5; std::cout << "setting alarm for 5 seconds..." << std::endl; thread_alarm alarm(secs); boost::thread thrd(alarm); thrd.join(); return 0; } Results in the following compilation error: c:\opt\include\boost\function\function_template.hpp(289): error C2664: 'void boost::function0<R,Allocator>::assign_to(Functor)' : cannot convert parameter 1 from 'const thread_alarm' to 'thread_alarm' with [ R=void, Allocator=int, Functor=thread_alarm ] I'm using Microsoft Studio .NET 2002 Thanks in advance for any help. Guillermo Martony

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Building 1.31.0 with intel-linux for Itanium 2
by Richard Hadsell 10 May '04

10 May '04

I am trying to build the Boost libraries on an Itanium 2 Linux machine using Intel C++ 8.0. The problem is that bjam is creating a directory path for the release versions that uses the string "ebug release" instead of "release". For example: MkDir1 bin/boost/libs/regex/build/libboost_regex.a/intel-linux/ebug release intel-linux-C++-action bin/boost/libs/regex/build/libboost_regex.a/intel-linux/ebug release/c_regex_traits.o ... Despite the directory that it creates with an embedded space, everything actually continues quite well, until it tries to run ranlib: intel-linux-Archive-action bin/boost/libs/regex/build/libboost_regex.a/intel-linux/ebug release/libboost_regex-il-1_31.a Ranlib bin/boost/libs/regex/build/libboost_regex.a/intel-linux/ebug release/libboost_regex-il-1_31.a ranlib: bin/boost/libs/regex/build/libboost_regex.a/intel-linux/ebug: No such file or directory ranlib bin/boost/libs/regex/build/libboost_regex.a/intel-linux/ebug release/libboost_regex-il-1_31.a ...failed Ranlib bin/boost/libs/regex/build/libboost_regex.a/intel-linux/ebug release/libboost_regex-il-1_31.a... I built bjam with this: build.sh intel-linux And I built the libraries with this: bjam -sTOOLS=intel-linux -sINTEL_PATH=/usr/local/intel/compiler80/ia64 --with-python-root=/usr --stagedir=stage -sBUILD="debug release <threading>single" stage Can anyone suggest what might be wrong with my system? It is a loaner, so everything is untested as far as I'm concerned. I have no idea what other tools in addition to Bjam itself might be involved in causing this problem. -- Dick Hadsell 914-259-6320 Fax: 914-259-6499 Reply-to: hadsell(a)blueskystudios.com Blue Sky Studios http://www.blueskystudios.com 44 South Broadway, White Plains, NY 10601

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Re: [Boost-users] Posix extended regexp
by Manish Madan 08 May '04

08 May '04

Thanks a lot for the help John, it works now regards Manish >>> john(a)johnmaddock.co.uk 5/6/2004 1:58:27 AM >>> > What am I doing wrong? > > Here's my short matching function: > > bool MatchRegExp(const std::string& matchThis, const std::string& > againstThis) > { > try > { > const boost::regex e(againstThis);//, > boost::regex_constants::icase); > return boost::regex_match(matchThis, e, > boost::regex_constants::extended); > } > catch(boost::bad_expression be) > { > return false; > } > > } You're passing the wrong constants in all the wrong places, it should have been: const boost::regex e(againstThis, boost::regex::extended); return boost::regex_match(matchThis, e, boost::match_default); You can omit the match_default flag (since it's the default anyway), and if you wanted case insensitive matching it would have been: const boost::regex e(againstThis, boost::regex::extended | boost::regex::icase); Oh, and don't forget to check the difference between regex_match and regex_search (the match version requires all of the text to match). John. _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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RE: [Boost-users] Re: shared_ptrs with std::mem_fn
by Mark Storer 08 May '04

08 May '04

> boost::mem_fn erases the need for a separate mem_fn_ref. If > http://www.boost.org/libs/bind/mem_fn.html fails to explain it to you, > please ask more specific questions. I thought I'd been pretty specific... guess not. Allow me to reiterate: Why doesn't std::mem_fun work with a container of boost::shared_ptr? I fiddled around with my compiler for a while (vc6), but ended up with a wildly unhelpful error message. Given the following lines of code (among others): --- typedef std::vector<boost::shared_ptr<std::string> > Strings; Strings strings; std::for_each( strings.begin(), strings.end(), std::mem_fun(std::string::size) ); --- my compiler puked up the following wildly useless error message: --- error C2664: 'mem_fun' : cannot convert parameter 1 from 'unsigned int (__thiscall std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >::*' to 'unsigned int (__thisca ll std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >::*' Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast --- Allow me to pull out those two types for easier viewing: unsigned int (__thiscall std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >::* unsigned int (__thiscall std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >::* Golly. Those 'two' types are about as related as you can get. So why won't std::mem_fun work through boost::shared_ptr's operator->? Here's the mem_fun that ships with VC6: --- template<class _R, class _Ty> class mem_fun_t : public unary_function<_Ty *, _R> { public: explicit mem_fun_t(_R (_Ty::*_Pm)()) : _Ptr(_Pm) {} _R operator()(_Ty *_P) const {return ((_P->*_Ptr)()); } private: _R (_Ty::*_Ptr)(); }; --- The relevant portion to our discussion is: "{return ((_P->*_Ptr()); }" which can be further boiled down to: return _P->_Ptr(); This looks an awful lot like it should work with a shared_ptr's operator->(). So why doesn't it? I admit that this is more of a C++ question than a boost one, but it's not too much of a tangent and I *am* curious. Mentioning mem_fun_ref in my previous post only served to muddy the waters. My apologies. --Mark Storer Senior Software Engineer Verity, Inc.

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shared_ptrs with std::mem_fn
by Steve Folly 07 May '04

07 May '04

Hi, I've converted a container to use shared_ptrs instead of regular pointers, now my for_each algorithm doesn't work: Before: class Attr; std::vector< Attr* > mAttributes; . . . std::for_each( mAttributes.begin(), mAttributes.end(), std::bind2nd( std::mem_fn( &Attr::Write ), output ) ); After: std::vector< shared_ptr<Attr> > mAttributes; Now it doesn't compile because (of course) Attr::Write is not a method of shared_ptr<Attr>. Do I have to use boost's bind and mem_fn objects instead of std? Thanks for any help. -- Regards, Steve.

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RE: [Boost-users] Re: shared_ptrs with std::mem_fn
by Mark Storer 07 May '04

07 May '04

> > Now it doesn't compile because (of course) Attr::Write is > not a method of > > shared_ptr<Attr>. > > > > Do I have to use boost's bind and mem_fn objects instead of std? > > Yes; bind and mem_fn handle this problem (and quite a few > others) automatically. Why is this a problem? I thought std::mem_fn called the function through the -> operator, which 'should' work (but obviously doesn't). I would think this would only crop up through mem_fun_ref, but then you wouldn't have a container of shared_ptr<Attr>, but Attr. --Baffled --Mark Storer Senior Software Engineer Verity, Inc.

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RE: [Boost-users] date_time clocks, microsec_clock, etc
by Darryl Green 07 May '04

07 May '04

> For those that need something portable we should be able to > get microsecond > resolution for Windows, Linux, and probably a few more... > > Jeff Microsecond resolution on linux? What interface provides this? I have a linux platform or 2 that I'm pretty sure won't provide it at present, but probably could with some kernel hacking, if only there was some sensible interface to connect it to user space. Darryl. ########################################################################## This e-mail is for the use of the intended recipient(s) only. If you have received this e-mail in error, please notify the sender immediately and then delete it. If you are not the intended recipient, you must not use, disclose or distribute this e-mail without the author's prior permission. We have taken precautions to minimise the risk of transmitting software viruses, but we advise you to carry out your own virus checks on any attachment to this message. We cannot accept liability for any loss or damage caused by software viruses. ##########################################################################

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how to install library in msvc
by kason aung 07 May '04

07 May '04

Dear all, I'm trying to install BGL on win 2k, vc++ 6 machine. I can't install BGL now. So if u have already successfully installed on msvc, i would like to know step-by-step installation procedure. I am looking forward to hearing good news from all of you. Thanks a lot for ur help and kindness. Regards, Kason _________________________________________________________________ Download games, logos, wallpapers and lots more at MSN Mobile! http://www.msn.com.sg/mobile/

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