October 2007 - Boost-users - lists.boost.org

boost-users [shared_array] comparing the value.
by chun ping wang 25 Oct '07

25 Oct '07

Hi I notice boost shared_array compares the pointer address not the pointer themselves. What would be the best way to compare the actual value of boost shared_array. 1.) shared_array<T> a; shared_array<T> b; 1.) return (a.len == b.len && (memcmp(a, b, len) == 0)); or 2.) if (a.len != b.len) return false; for (ptrdiff_t i = 0; i != a.len; ++i) if(a[i] != b[i]) return false; One that works ALL the times.

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Building boost::system
by Simon Pickles 25 Oct '07

25 Oct '07

Hi, Since the new update of boost::asio, I need to build boost::system. I built it using bjam in the boost/system/build directory, and it built: boost_system_vc80-gd-1_34_1.lib but my compiler needs: libboost_system-vc80-mt-gd-1_34_1.lib I'm not sure what the difference between the boost and libboost version, but I know the mt is multithreaded.... Can anyone advise? Thanks Si

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boost-1_34_1 in program_options getting compiling error : parse error before >
by Salles, Joaquim Campos 25 Oct '07

25 Oct '07

Hello, I'm using boost.1.34 and when I try to compile I get the following error: /usr/local/include/boost-1_34_1/boost/program_options/parsers.hpp:156: parse error before `>' I also try: ./configure --with-libraries=program_options Make And get the some error. What is my mistake? Thanks, Joaquim P.S. About g++ g++ -v Reading specs from /usr/lib/gcc-lib/i386-redhat-linux/2.96/specs gcc version 2.96 20000731 (Red Hat Linux 7.3 2.96-110)

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Boost Problem
by question boost 25 Oct '07

25 Oct '07

Hi, my program makes use of Boost(Code Blocks). The arrangement of my files is the following: 1 in the directory of the source files of my program there is the directory "boost" containing the following directories: "filesystem", "config", "iterator","range","detail", "mpl", "preprocessor", "tools" and the file boost-build.jam. 2 The file that makes use of boost in my project contains the following lines: #include <string> using namespace std; #include "boost\filesystem\path.hpp" #include "boost\filesystem\operations.hpp" using namespace boost::filesystem; At compilation I get the message :"boost/preprocessor/config/config.hpp" no such file or directory and several other similar messages about other files of the same directory and about other files of the "mpl" directory. What goes wrong? Thank You David _________________________________________________________________ Découvrez le blog Messenger Le Meilleur du Web : toutes les vidéos qui buzzent le plus sur Internet ! http://meilleurduweb.spaces.live.com/

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Thread Group fails to run
by Apostolos Apostolidis 25 Oct '07

25 Oct '07

Hi all. I have developed some code allowing a thread group of 500 threads to run. However, as soon as the 381st thread is spawned, I get the following runtime error : terminate called after throwing an instance of 'boost::thread_resource_error' what(): boost::thread_resource_error The Boost documentation does not clarify the nature of the error, so I was wondering if anyone can help me out here. The (simple) program code follows. #include <boost/thread/mutex.hpp> #include <boost/thread/thread.hpp> #include <boost/bind.hpp> using namespace std; boost::mutex io_mutex; void foo(int i) { boost::mutex::scoped_lock lock(io_mutex); cout << i << endl; } int main(int argc, char *arvg[]) { boost::thread_group tg; for(int i = 0;i < 500;i++) tg.create_thread(boost::bind(&foo,i)); tg.join_all(); }

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Using mpl::remove with template paramter
by spider tong 25 Oct '07

25 Oct '07

Hi all, I'm trying to use mpl::remove to do some processing with a template parameter, like this template<typename T0, typename T1=null_type, ... typename Tn=null_type> struct my_class { typedef mpl::vector<T0, T1,...Tn> my_vector; typedef mpl::remove<my_vector, null_type>::type my_non_vector; //failed here }; Compiler report that my_vector is not derive from my_class<T0, T1,..Tn>. It seems that 'remove' would test the sequence at once, and my_vector still un_known yet, so it fails, is this guess right? //-------------------------------------------------------------------------- And I've tried this fusion too: teypdef vector<Class1, Class2, null_type, null_type> vec; vec v; fusion::for_each<v, print>; it seems that it iterate 4 times, not 2, even size(vec) return 2. It seems only evaluate will skip null_type, iterate will go through all member, is my guess right? Best Regards Spider

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Re: [Boost-users] Request to know about "dynamic expression evaluation"
by Borse, Ganesh 25 Oct '07

25 Oct '07

Hi, You recommended checking the "expression templates". However, expression templates (xpressive) provides the means of parsing the input expressions in to tokens. It does not have the support for evaluating these expressions. --- please correct me if I'm wrong. Thanks, Ganesh > _____________________________________________ > From: boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org <mailto:boost-users-bounces@lists.boost.org> ] On Behalf Of boost-users-request(a)lists.boost.org > Sent: 24 October 2007 02:29 > To: boost-users(a)lists.boost.org > Subject: Boost-users Digest, Vol 1428, Issue 3 > > Send Boost-users mailing list submissions to > boost-users(a)lists.boost.org > > To subscribe or unsubscribe via the World Wide Web, visit > http://lists.boost.org/mailman/listinfo.cgi/boost-users <http://lists.boost.org/mailman/listinfo.cgi/boost-users> > or, via email, send a message with subject or body 'help' to > boost-users-request(a)lists.boost.org > > You can reach the person managing the list at > boost-users-owner(a)lists.boost.org > > When replying, please edit your Subject line so it is more specific than "Re: Contents of Boost-users digest..." > > > Today's Topics: > > 1. Re: Request to know about "dynamic expression evaluation" > (Robert Ramey) > 2. seeding a boost::random number generator...? (Graham Reitz) > 3. Thread Library Problem (Andres Herrera) > 4. boost::serialization Is there any way to get rid of compiler > warnings(C4103, ...) on VC++ 2005? (Oleg Udovenko) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Tue, 23 Oct 2007 09:15:17 -0700 > From: "Robert Ramey" <ramey(a)rrsd.com> > Subject: Re: [Boost-users] Request to know about "dynamic expression > evaluation" > To: boost-users(a)lists.boost.org > Message-ID: <ffl6mi$25v$1(a)ger.gmane.org> > Content-Type: text/plain; charset="iso-8859-1" > > Request to know about "dynamic expression evaluation"Look for "expression templates" > > Robert Ramey > "Borse, Ganesh" <ganesh.borse(a)credit-suisse.com> wrote in message news:F444CAE5E62A714C9F45AA292785BED327C3BE87@esng11p33001.sg.csfb.com <news:F444CAE5E62A714C9F45AA292785BED327C3BE87@esng11p33001.sg.csfb.com> ... > Hi, > I would like to perform the dynamic expression evaluation in my c++ application. > The dynamic expressions are like the SQL queries. > Since the expressions could be nested & hence the parsing & evaluation of such expressions is reducing the performance of my application. > > May I please know, whether BOOST provides a support for such dynamic expression evaluation in C++? > Please guide. > > Thanks in advance for the guidance. > > Regards, > Ganesh > > > ============================================================================== > Please access the attached hyperlink for an important electronic communications disclaimer: > > http://www.credit-suisse.com/legal/en/disclaimer_email_ib.html <http://www.credit-suisse.com/legal/en/disclaimer_email_ib.html> > ============================================================================== > > > > ------------------------------------------------------------------------------ > > > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users <http://lists.boost.org/mailman/listinfo.cgi/boost-users> >

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The arrangement of a boost program
by question boost 25 Oct '07

25 Oct '07

Hi, 1 My program under Code Blocks makes use of Boost. The arrangement of my files is the following: in the directory of the source files of my program there is the directory "boost" containing the following directories: "filesystem", "config", "iterator","range","detail", "mpl", "preprocessor", "tools" and the file boost-build.jam. 2 The file that makes use of boost in my project contains the following lines: #include <string> using namespace std; #include "boost\filesystem\path.hpp" #include "boost\filesystem\operations.hpp" using namespace boost::filesystem; 3 At compilation I get the message :"boost/preprocessor/config/config.hpp" no such file or directory and several other similar messages about other files of the same directory and about other files of the "mpl" directory. I've followed all the instructions here http://www.boost.org/doc/html/jam/building.html and here http://www.boost.org/doc/html/bbv2/installation.html At end of step 4 of http://www.boost.org/doc/html/bbv2/installation.html, the problem at compilation remains the same. Thank you for your response. David _________________________________________________________________ Retrouvez Windows Live Messenger sur votre mobile ! http://www.messengersurvotremobile.com

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Compiling 1.34.1 on OpenSUSE 10.3
by Ruediger Berlich 25 Oct '07

25 Oct '07

Hi there, OpenSUSE 10.3 is still delivered with Boost 1.33.1 . Hence I've downloaded Boost 1.34.1 and tried to compile it. I ran the configure script and then make. The resulting bjam immediately dies with an error: ./tools/jam/src/bin.linuxx86/bjam --user-config=user-config.jam /bin/sh: line 1: 2090 Speicherzugriffsfehler ./tools/jam/src/bin.linuxx86/bjam --user-config=user-config.jam "Speicherzugriffsfehler" means "memory access violation". This is on a Pentium-D dual-core system (4GB main memory) running with a 32-bit Linux kernel 2.6.22, g++ 4.2.1 . Does anyone have experience with this constellation ? Compilation of 1.34 worked fine on OpenSUSE 10.2 . Thanks and best regards, Ruediger

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[boost-users] anyways to flatten a stl container.
by chun ping wang 24 Oct '07

24 Oct '07

Is their some kind of method to flatten a stl container... example [[1, 4], [a,b, c], [b, [e]] ] becomes [1, 4, a, b, c, b, e]

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