July 2008 - Boost-users - lists.preview.boost.org

[BOOST::ASIO] How can I catch disconnect event from remote side ?
by Ken zhang 29 Jul '08

29 Jul '08

Hi Dear all. How can I catch the disconnect event from remote side in boost::asio? Thanks

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Specifying which version of gcc to use when compiling boost
by Simon Lacroix 29 Jul '08

29 Jul '08

Hello all, I have a system with both gcc version 3.4 and gcc version 3.2 installed (distro is RHE4). I am trying to compile the filesystem package using 3.2 but for some reason it always seem to pick gcc 3.4. I tried the following (as specified in section 5.2.2 of the unix getting started guide) : ./configure .. -with-toolset=gcc-3.2.3 Performing a make after that tells me that it doesn't know anything about the tool and then give me a list of tool (basically all tools name with no version) Doing this however works but it uses version 3.4 ./configure .. -with-toolset=gcc Both cc and gcc executable points to gcc 3.2.3 the version that I want to use. Anybody can point me out what I am missing ? Thanks in advance ! Simon

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Re: [Boost-users] compiling boost on AIX gives pthread errors
by Andrej van der Zee 29 Jul '08

29 Jul '08

Hi, > We are using AIX 5.3 and the 4.2.0 compiler and obviously require IBM's mpCC > MPI compiter to be supported, out-of-the-box. You should not be using the gcc compiler that is shipped with AIX 5.3 because it is hopelessly broken, just like their alternative binary version from the official IBM website. I wonder why? Note that IBMs compiler xlc/c++ costs almost 4000 Euro's for one user's lisence. And still I wonder why they ship a broken gcc compiler with their AIX distribution ;) Luckily you also can get binary distrubutions from here: http://gcc.gnu.org/install/binaries.html. Besides that there is a patch you should apply to the Boost source tree to make it all work (or you can use boost-trunk from SVN). Then you will be able to compile boost on AIX 5.3, but you will get some occasional complains from the linker and/or compiler. Anyway, I would be greatful if Boost would officially start to support gcc on AIX! Hopefuly it will be picked up soon... Cheers, Andrej __________________________________________________________ Not happy with your email address?. Get the one you really want - millions of new email addresses available now at Yahoo! http://uk.docs.yahoo.com/ymail/new.html

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XML library?
by Michiel Helvensteijn 29 Jul '08

29 Jul '08

I was surprised not to find an XML parser/generator library in boost. Or is it hidden somewhere? Is it planned for a future release, perhaps? In the meantime, can anyone recommend another open source C++ XML library I can use (with DOM parser)? Thanks! -- Michiel Helvensteijn

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Re: [Boost-users] compiling boost on AIX gives pthread errors
by Henrik Nagel 29 Jul '08

29 Jul '08

K. Noel Belcourt wrote: > > We don't test with gcc on Aix, but we should. > I am having trouble installing boost 1.35.0 on AIX too. How about porting boost to AIX? We have an IBM p575+ computer with AIX that you can get an account on for testing purposes. We are using AIX 5.3 and the 4.2.0 compiler and obviously require IBM's mpCC MPI compiter to be supported, out-of-the-box. Best regards, Henrik -- View this message in context: http://www.nabble.com/compiling-boost-on-AIX-gives-pthread-errors-tp1733930… Sent from the Boost - Users mailing list archive at Nabble.com.

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Suggestions for Simple Expression Evaluation
by Richard L. Aurbach 28 Jul '08

28 Jul '08

I am looking for some code to handle simple expression evaluation -- cases like "a | b | c", or "(a + b)/2", where 'a', 'b', and 'c' are named constants that I can evaluate by lookup. I.e., code to evaluate simple expressions to produce integer results. I'm looking for something light-weight and easy to use -- something that justifies a decision to look elsewhere rather than writing the 10- million-and-first simple evaluator. (I know that lots of folks have written this type of code as a homework assignment in a data structures course. As it happens, I don't have an old assignment to look up and am hoping to spare the time doing it now :-) ) I didn't see anything in the boost library that didn't appear to be incredible overkill, but I'm happy to be proven wrong about that. Anyway, I would be very interested in some suggestions (using boost or otherwise) that can help me implement run-time evaluation of simple expressions without a major investment in the size or complexity of my application. Cheers, Rick Aurbach Aurbach & Associates, Inc.

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new version
by Gang Ma 28 Jul '08

28 Jul '08

Thanks, guys. I change my code a bit. The results are right. But I suspect it never used thread, but excute the thread one by one. new code void mtread(char* filename,const int stidx, const int edidx,int id) { fstream infile; infile.open(filename); string line; int linenum = 0; if (infile.good()){ while (! infile.eof()) { boost::mutex::scoped_lock lock(io_mutex); // infile.seekg(linenum,ios::beg); getline(infile,line); if (linenum>=stidx && linenum<=edidx){ cout<<id << " : " <<line<<endl; //cout<<linenum<<endl; linenum++; } else { linenum++; if (linenum>edidx) break; } } } else { cerr<< "file " << filename << " cannot be opened for reading" <<endl; } infile.close(); } I got the same results running the program twice. 1 : 1 1 : 2 1 : 3 1 : 4 1 : 5 2 : 6 2 : 7 2 : 8 2 : 9 2 : 10 Thank for your helps. regards, gma

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Re: [Boost-users] Initialization of boost::asio::ip::tcp::socket geneates unhandled exception
by Igor R 28 Jul '08

28 Jul '08

Hi, The problem is somewhere in the design of your program, so it's hardly possible to find out it from this short description. Sounds like dangling reference/pointer - probably, io_service was destroyed/not initialized yet? (remember that the members are initialized in the order of their definition) 2008/7/28, Jean-Sebastien Stoezel <js.stoezel(a)gmail.com>: > Hi, > > I'm getting confused by the unhandled exception I get when > initializing a TCP socket. This happens when the socket is > instantiated and initialized with an IO service object, from the > constructor of a class called CProcessor. > > Here are the variables declaration, inside the class: > > boost::asio::ip::tcp::socket m_Socket; > boost::asio::io_service m_IoService; > > Here is what the default constructor looks like for this class: > CProcessor::CProcessor(void): > m_Socket(m_IoService) > {} > > The exception is generated by this constructor, as soon as the > m_Socket object is initialized. > > The type of unhandled exception I got is as follow: > "Unhandled exception at whatever in hatever.exe: 0xC0000005: Access > violation reading location 0xcccccce0." > The program breaks in win_mutex.hpp, at a line calling: > ::EnterCriticalSection(&crit_section_); > > I run VS9. > > Any idea?! > > Thanks, > Jean > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users >

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Release 1.36.0 Beta
by Lothar Werzinger 28 Jul '08

28 Jul '08

Hi, on http://www.boost.org/community/index.html kit indicates that 1.36.0 Beta should be available. However I found no link on the news or download page. Where can I get the beta? Don't you want the beta to be tested by a wider audience? How would you do that if it is not publicly available? Lothar -- Lothar Werzinger Dipl.-Ing. Univ. framework & platform architect Tradescape Inc. - Enabling Efficient Digital Marketplaces 1754 Technology Drive, Suite 128 San Jose, CA 95110 web: http://www.tradescape.biz

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multithreaded read a file using thread lib
by Gang Ma 28 Jul '08

28 Jul '08

Hi, I tried to use boost/thread library to write a program to read a large text file. The program compiled but did not get the right answer. I am not sure my usage of the library is correct. I appreciate your helps. Here are the code: #include <iostream> #include <fstream> #include <string> #include <boost/thread/thread.hpp> #include <boost/thread/mutex.hpp> #include <boost/bind.hpp> #include <SQLAPI.h> //#include "stdafx.h" boost::mutex io_mutex; using namespace std; void mtread(char* filename,const int stidx, const int edidx,int id) { fstream infile; infile.open(filename); string line; if (infile.good()){ for (int linenum=stidx; linenum<=edidx;linenum++) { boost::mutex::scoped_lock lock(io_mutex); infile.seekg(linenum,ios::beg); getline(infile,line); cout<<id << " : " <<line<<endl; } } else { cerr<< "file " << filename << " cannot be opened for reading" <<endl; } infile.close(); } int main(int argc, char** argv){ boost::thread thrd1(boost::bind(&mtread, argv[1],0,4,1)); boost::thread thrd2(boost::bind(&mtread, argv[1],5,9,2)); thrd1.join(); thrd2.join(); return 0; } I would like thread1 read linie 0-4 and thread2 read line 5-9. My dummy test file has 10 lines, each line is 1,2, 3...,10 etc. My output is 2 : 2 : 3 2 : 2 : 1 : 1 1 : 1 : 1 : 2 1 : 2 : 4 regards, Gang Ma

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