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Boost.Random: Missing definitions of to static constants
by Daniel Krügler 30 Aug '05

30 Aug '05

The class template xor_combine<> from xor_combine.hpp declares 3 static constant members has_fixed_range (bool), shift1 (int), and shift2 (int), but **defines** only has_fixed_range. I propose, that proper definitions for shift1 and shift2 should be provided in the already existing BOOST_NO_INCLASS_MEMBER_INITIALIZATION block, too. Greetings from Bremen, Daniel Krügler

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incorrect random library equality implementation?
by Steven Solie 30 Aug '05

30 Aug '05

The Boost 1.33.0 random library equality operators seem to be implemented incorrectly. For example, in file random/lagged_fibonacci.hpp starting at line 390 we have the following: friend bool operator==(const lagged_fibonacci_01& x, const lagged_fibonacci_01& y) { return x.i == y.i && std::equal(x.x, x.x+long_lag, y.x); } The std::equal() call is comparing an array of doubles using operator == which I thought was impossible for floating point types due to their inexact nature et al. This is causing all the test cases using floating point types to fail on AmigaOS with GCC 3.4.4. Is this an implementation error or am I missing something? --Steven

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boost::thread waiting problem
by Ovanes Markarian 30 Aug '05

30 Aug '05

Hello, I have the following scenario: Evaluate String Stream until a certain string is found or a time has occured. The string evaluation is made not in a single function, but using a stream iterator and later an evaluator of the retrieved data. I have an iterator class as function object where a boost::shared_ptr<boost::timed_mutex> mutex; member is defined. It has 2 functions: operator()() which is a worker function of the time_out thread and an iteratorion function. Now I start when entered for the first time the iteration function the time_out thread. The time_out thread should block until the time_out elapses or the another function has found the desired string from the stream. my code looks like: operator()() { boost::timed_mutex::scoped_timed_lock lock(*mutex, true); boost::condition c; boost::xtime xt; boost::xtime_get(&xt, boost::TIME_UTC); xt.sec +=20; c.timed_wait(lock, xt); } My approach was to use the mutex object for syncronization. I assumed that it is locked as long as c.timed_wait(...) is waiting. So I try to lock this object in the other thread. If the mutex object can not be locked the worker thread is still waiting, otherwise time_out elapsed. >From the Rationale section of the thread docs I heavily understand which locking strategy is used for timed_mutex. Can someone point me to a the correct place with documentation and say if this approach will work or I should consider a redesign? With Kind Regards, Ovanes Markarian

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Re: [Boost-users] [boost::bind] How use with fn objects?
by BRIDGES Dick 30 Aug '05

30 Aug '05

> -----Original Message----- > From: boost-users-bounces(a)lists.boost.org [mailto:boost-users- > bounces(a)lists.boost.org] On Behalf Of Rene Rivera > Sent: Monday, August 29, 2005 12:30 PM > To: boost-users(a)lists.boost.org > Subject: Re: [Boost-users] [boost::bind] How use with fn objects? > > BRIDGES Dick wrote: [snip] > > I'm trying to pass a function object that takes no > > parameters to a boost::thread constructor and cannot > > get it right. [snip] > Either: > > int > main( int argc, char **argv ) { > Foo f; > boost::thread doit( boost:bind(Foo::operator(),&f)() ); > doit.join(); > return 0; > } > > Or: > > int > main( int argc, char **argv ) { > Foo f; > boost::thread doit( f ); > doit.join(); > return 0; > } > > Should work. > > > -- > -- Grafik - Don't Assume Anything > -- Redshift Software, Inc. - http://redshift-software.com > -- rrivera/acm.org - grafik/redshift-software.com > -- 102708583/icq - grafikrobot/aim - Grafik/jabber.org After I figured out I had to use boost::ref(f) with my real class, the second form worked fine. I had a problem with the first form though. <code> boost::thread doit( boost::bind(Foo::operator(),&f)() ); </code> Yielded the following [edited to fit] result: <result> g++ -D_REENTRANT -I/usr/local -I/usr/local/boost_1_33_0 -I/usr/local/include -O0 -g3 -Wall -c -fmessage-length=0 -Wno-non-virtual-dtor -omain.o ../main.cpp ../main.cpp: In function `int main(int, char**)': ../main.cpp:22: error: invalid use of non-static member function `void my_namespace::Foo::operator()()' /usr/local/boost_1_33_0/boost/bind.hpp: At global scope: /usr/local/boost_1_33_0/boost/bind.hpp: In instantiation of `boost::_bi::result_traits<boost::_bi::unspecified, void (my_namespace::Foo::)()>': /usr/local/boost_1_33_0/boost/bind/bind_template.hpp:15: instantiated from `boost::_bi::bind_t<boost::_bi::unspecified, void (my_namespace::Foo::)(), boost::_bi::list1<boost::_bi::value<my_namespace::Foo*> > >' ../main.cpp:22: instantiated from here /usr/local/boost_1_33_0/boost/bind.hpp:63: error: `void (my_namespace::Foo::)()' is not a class, struct, or union type /usr/local/boost_1_33_0/boost/bind/bind_template.hpp: In instantiation of `boost::_bi::bind_t<boost::_bi::unspecified, void (my_namespace::Foo::)(), boost::_bi::list1<boost::_bi::value<my_namespace::Foo*> > >': ../main.cpp:22: instantiated from here /usr/local/boost_1_33_0/boost/bind/bind_template.hpp:15: error: no type named `type' in `struct boost::_bi::result_traits<boost::_bi::unspecified, void (my_namespace::Foo::)()>' /usr/local/boost_1_33_0/boost/bind/bind_template.hpp:18: error: no type named `type' in `struct boost::_bi::result_traits<boost::_bi::unspecified, void (my_namespace::Foo::)()>' [snip bind_template.hpp:24 thru bind_template.hpp:138] /usr/local/boost_1_33_0/boost/bind/bind_template.hpp:143: error: no type named `type' in `struct boost::_bi::result_traits<boost::_bi::unspecified, void (my_namespace::Foo::)()>' /usr/local/boost_1_33_0/boost/bind.hpp: In instantiation of `boost::_bi::bind_t<boost::_bi::unspecified, void (my_namespace::Foo::)(), boost::_bi::list1<boost::_bi::value<my_namespace::Foo*> > >': ../main.cpp:22: instantiated from here /usr/local/boost_1_33_0/boost/bind/bind_template.hpp:160: error: field `boost::_bi::bind_t<boost::_bi::unspecified, void (my_namespace::Foo::)(), boost::_bi::list1<boost::_bi::value<my_namespace::Foo*> > >::f_' invalidly declared method type ../main.cpp: In function `int main(int, char**)': ../main.cpp:22: error: no match for call to `(boost::_bi::bind_t<boost::_bi::unspecified, void (my_namespace::Foo::)(), boost::_bi::list1<boost::_bi::value<my_namespace::Foo*> > >) ()' /usr/local/boost_1_33_0/boost/bind.hpp: In constructor `boost::_bi::bind_t<R, F, L>::bind_t(F, const L&) [with R = boost::_bi::unspecified, F = void (my_namespace::Foo::)(), L = boost::_bi::list1<boost::_bi::value<my_namespace::Foo*> >]': /usr/local/boost_1_33_0/boost/bind.hpp:1403: instantiated from `boost::_bi::bind_t<boost::_bi::unspecified, F, typename boost::_bi::list_av_1<A1>::type> boost::bind(F, A1) [with F = void (my_namespace::Foo::)(), A1 = my_namespace::Foo*]' ../main.cpp:22: instantiated from here /usr/local/boost_1_33_0/boost/bind.hpp:861: error: invalid use of non-static member function make: *** [main.o] Error 1 make: Target `all' not remade because of errors. </result> Thank you (and Peter Dimov) for your assistance. BTW I'm still unclear on *why* (f) works. It doesn't look like any pointer to member function I've read about. Isn't f.operator() treated like any other member function? Can someone suggest something to read that might help me understand? Thanks again for your help. Regards, Dick Bridges

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[Threads] Doc build error?
by Bruno Martínez 30 Aug '05

30 Aug '05

The documentation of boost.threads seems to be built wrong. In several places sentences don't make sense, and words are missing. Some examples are: " Introduction ??? allows C++ programs to execute as multiple, asynchronous, independent threads-of-execution. " " It is possible to write thread-safe implementations of these by using thread specific storage (see boost::thread_specific_ptr), and several C++ compiler vendors do just that. The technique is well-know and is explained in ???. " What's wrong? Bruno

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Re: [Boost-users] Boost.Thread memory leak reported
by Sohail Somani 29 Aug '05

29 Aug '05

> -----Original Message----- > From: boost-users-bounces(a)lists.boost.org > [mailto:boost-users-bounces@lists.boost.org] On Behalf Of Elisha Berns > Sent: Monday, August 29, 2005 4:17 PM > To: boost-users(a)lists.boost.org > Subject: Re: [Boost-users] Boost.Thread memory leak reported > > > Peter Dimov wrote: > > > C++ doesn't guarantee a particular initialization order for > file scope > > objects in different translation units, so we have to > resort to local > > statics or call_once. > > I hear you, I hear the point. I don't have a good solution > to this, but I hope someone does! What about having a single singleton solely responsible for initializing all the other ones?

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Boost.Iostreams: mapped_file_source can't open read only files
by Elisha Berns 29 Aug '05

29 Aug '05

Hi again, Odd, today I have only had PROBLEMS with boost. I guess it's just one of those days. Anyways, the open_impl() method for iostreams::mapped_file_source just doesn't open any mappings for files. I realize that it is reused by the mapped_file class, but that is what seems to cloud the design, flow and working of it as it needs to please everyone here, and it doesn't. It always throws in this location: pimpl_->mapped_handle_ = ::CreateFileMappingA( pimpl_->handle_, NULL, readonly ? PAGE_READONLY : PAGE_READWRITE, 0, 0, p.path.c_str() ); if (pimpl_->mapped_handle_ == NULL) { detail::cleanup_and_throw(*pimpl_, "couldn't create mapping"); } However, if I use just the raw Win32 APIs all works fine: HANDLE hFile = CreateFile(szFile, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_READONLY, NULL); if ( hFile == INVALID_HANDLE_VALUE ) return; HANDLE hFileMapping = CreateFileMapping(hFile, NULL, PAGE_READONLY, 0, 0, NULL); if ( hFileMapping == 0 ) { CloseHandle(hFile); return; } void* pView = ::MapViewOfFile(hFileMapping, FILE_MAP_READ, 0, 0, 0); if ( pView == 0 ) { CloseHandle(hFileMapping); CloseHandle(hFile); return; } Anyways, here my desire is to use the boost libraries as an insulation layer to enable writing cross-platform C++, but obviously if it doesn't work that idea doesn't go too far. So I really hope this gets addressed. Many thanks, Elisha Berns e.berns(a)computer.org tel. (310) 556 - 8332 fax (310) 556 - 2839

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[boost::bind] How use with fn objects?
by BRIDGES Dick 29 Aug '05

29 Aug '05

The documentation gives examples for int operator()(int a, int b)... bool operator()(long a, long b)... that use _1 to represent the first parameter (i.e., 'a'). I'm trying to pass a function object that takes no parameters to a boost::thread constructor and cannot get it right. <my_code> class Foo { void operator()() { /* do something */ return; } } int main( int argc, char **argv ) { Foo f; boost::thread doit( boost:bind<void>(f,_1)() ); doit.join(); return 0; }</my_code> Isn't the '_1' required for the this pointer? If it's not required, what is the correct form? Thanks in advance for any help. Regards, Dick Bridges "Multithreading is just one damn thing after, before, or simultaneous with another." Scott Meyers and Andrei Alexandrescu

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shared_ptr & polymorphic_iarchive in 1.33.0
by Sergey Skorniakov 29 Aug '05

29 Aug '05

Has anybody tested loading of shared_ptr with polymorphic archives? All that I manage to achive is just a couple of errors: c:\boost_1_33_0\boost\archive\detail\interface_iarchive.hpp(73) : error C2039: 'basic_iarchive' : is not a member of 'boost::archive::polymorphic_iarchive' c:\boost_1_33_0\boost\archive\polymorphic_iarchive.hpp(52) : see declaration of 'boost::archive::polymorphic_iarchive' c:\boost_1_33_0\boost\archive\detail\interface_iarchive.hpp(72) : while compiling class-template member function 'void boost::archive::detail::interface_iarchive<Archive>::lookup_helper(const boost::serialization::extended_type_info *const ,boost::shared_ptr<T> &)' with [ Archive=boost::archive::polymorphic_iarchive, T=void ] c:\boost_1_33_0\boost\archive\polymorphic_iarchive.hpp(54) : see reference to class template instantiation 'boost::archive::detail::interface_iarchive<Archive>' being compiled with [ Archive=boost::archive::polymorphic_iarchive ] c:\boost_1_33_0\boost\archive\detail\interface_iarchive.hpp(73) : error C2662: 'boost::archive::detail::basic_iarchive::lookup_basic_helper' : cannot convert 'this' pointer from 'boost::archive::polymorphic_iarchive' to 'boost::archive::detail::basic_iarchive &' Reason: cannot convert from 'boost::archive::polymorphic_iarchive' to 'boost::archive::detail::basic_iarchive' Conversion requires a second user-defined-conversion operator or constructor

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Re: [Boost-users] [typeof] question: BOOST_TYPEOF_COMPLIANT
by Bulygin, Sergey 29 Aug '05

29 Aug '05

>>#include <boost/typeof/typeof.hpp> >>#define BOOST_TYPEOF_COMPLIANT >Just move define before the include, otherwise it has no effect. >Regards, >Arkadiy I tried that before, but it didn't give an effect. Now I discovered the problem - that was "#include <boost/typeof/typeof.hpp>" in the precompiled header file. That way typeof.hpp in the cpp was ignored, and BOOST_TYPEOF_COMPLIANT definition didn't make its job. Thanks! Sergey

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