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

Understanding how enable_if works.
by Michael Marcin 11 Aug '06

11 Aug '06

Hi, I'm new to boost / generic programming and I'm trying to understand how enable_if works because I don't like using things I don't understand. I made a simple example which I thought would have the same behavior as using enable_if but doesn't. I've attached the test could someone take a look and explain why enable_if works and the other doesn't. Thanks begin 666 main.cpp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a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` ` end

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ifstream question
by pktao＠uwm.edu 10 Aug '06

10 Aug '06

Im having trouble calling an input file stream from inside a function and was hoping if anyone can help me with a solution. Im compiling with MSVC++ 8.0. Below is a detailed description of the problem: The input file that Im trying to read is pt03-test-1.txt. Its just a text file with 2 integer values in a single column: 24 35 the path to the file is : /tao/data/pt03-test-1.txt The following code works: #include <iostream> #include <vector> #include <fstream> #include <boost/filesystem/operations.hpp> #include <boost/filesystem/fstream.hpp> int main() { boost::filesystem::ifstream inputDataStream("/tao/data/pt03-test-1.txt"); int mobilityIndexMarker = 0; inputDataStream >> mobilityIndexMarker; std::cout << mobilityIndexMarker << std::endl; return (0); }; Encapsulating the lines in main in a separate function breaks the code: #include <iostream> #include <vector> #include <fstream> #include <boost/filesystem/operations.hpp> #include <boost/filesystem/fstream.hpp> boost::filesystem::ifstream inputDataStream; //declaration of inputDataStream void trialOnsetWrite() { int mobilityIndexMarker = 0; inputDataStream >> mobilityIndexMarker; std::cout << mobilityIndexMarker << std::endl; }; int main() { boost::filesystem::ifstream inputDataStream("/tao/data/pt03-test-1.txt"); trialOnsetWrite(); return (0); }; Very Very Appreciative, Patrick

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usage cregex_iterator
by Winson Yung 10 Aug '06

10 Aug '06

Hi all, I am trying to use cregex_iterator, but reading the doc doesn't seem to help me understand the usage of the API. If I supply a regular expression, is the following code correctly get the starting position of each occurance of the string "hello world here" in the buffer? sample code like this: int nextPos[100]; char *pBuf = NULL; // pBuf will be point to a buffer NULL terminated ............................ regex expr("hello world here", regex_constants::perl | regex_constants::icase); cregex_iterator h1(pBuf, pBuf + std::strlen(pBuf), expr, 1), h2; int i = 0; while (i < 100 && h1 != h2) { nextPos[i] = (*h1).position(0); h1++; i++; }

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implementation of serialization code cannot be done in cpp file
by Cheok Yan Cheng 10 Aug '06

10 Aug '06

I am using VC++ 2003. I realize that when I provide the code defination for save and load on cpp file, the following error will occur: animal error LNK2019: unresolved external symbol "private: void __thiscall cat::save<class boost::archive::text_oarchive>(class boost::archive::text_oarchive &,unsigned int)const " (??$save@Vtext_oarchive@archive@boost@@@cat@@ABEXAAVtext_oarchive@archive@boost@@I@Z) referenced in function "public: static void __cdecl boost::serialization::access::member_save<class boost::archive::text_oarchive,class cat const >(class boost::archive::text_oarchive &,class cat const &,unsigned int)" (??$member_save@Vtext_oarchive@archive@boost@@$$CBVcat@@@access@serialization@boost@@SAXAAVtext_oarchive@archive@2@ABVcat@@I@Z) ------ cat.h ------ #ifndef CAT_H #define CAT_H #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> class cat { private: friend class boost::serialization::access; template<class Archive> void save(Archive & ar, const unsigned int version) const; template<class Archive> void load(Archive & ar, const unsigned int version); BOOST_SERIALIZATION_SPLIT_MEMBER() }; #endif ------- cat.cpp ------- #include "cat.h" template<class Archive> void cat::save(Archive & ar, const unsigned int version) const { } template<class Archive> void cat::load(Archive & ar, const unsigned int version) { } -------- main.cpp -------- #include <iostream> #include <cassert> #include <string> #include <sstream> #include <fstream> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> #include "cat.h" int main() { const cat c; // make an archive std::ofstream ofs("test"); boost::archive::text_oarchive oa(ofs); oa << c; } However, if I remove cat.cpp file during compilation and having the code defination at header file as follow, the code compiled with no problem. May I know how I can put my serialization code at cpp file instead of header file? Thank you very much! The reason I want to do so is that I need to perform class forwarding in certain classes. Due to the reason class forwarding unable to provide a full information of a class at header level, serialization code can only be written in cpp file level. ------ cat.h ------ #ifndef CAT_H #define CAT_H #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> class cat { private: friend class boost::serialization::access; template<class Archive> void save(Archive & ar, const unsigned int version) const{} template<class Archive> void load(Archive & ar, const unsigned int version) {} BOOST_SERIALIZATION_SPLIT_MEMBER() }; #endif __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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[BGL] Is there a way to avoid a sequence of edges while traversing a Graph?
by Rohit Wadhwa 10 Aug '06

10 Aug '06

The problem we are trying to solve is as follows: The figure below describes a section of a graph. D ----------*--------------- | | | B F ----------*-------*-------* C | | | | | | ------------------*-------* A E We want to achieve the following via traversal: 1. Avoid the sequence from A->B->C->D. 2. Still be able to traverse to D from A via other paths, if available (eg. A->E, E->F, F->B, B->C, and C->D) We would like to be able to represent this in a graph (BGL) in a manner that will allow algorithms (such as DSP, connected_components etc.) to not take the 'prohibited path' into account. Is there a way to disable a particular path via traversal? Thanks in advance, Rohit.

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[program_options] changes in CVS are partial correct
by Ovanes Markarian 10 Aug '06

10 Aug '06

Hello, what should I do if changes in CVS are partial correct? Should I post correct one here or directly to CVS? With Kind Regards, Ovanes Markarian

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boost::logging - Problem with scoped log example.
by boost＠david-williams.info 10 Aug '06

10 Aug '06

Hi guys, I've just been experimenting with boost::logging. I've got some of the examples to work but can't get scoped logging to work. The folowing code should work, according http://www.torjo.com/code/log/scoped.html 1 : #include <boost/log/log.hpp> 2 : #include <boost/log/functions.hpp> 3 : 4 : using namespace boost::logging; 5 : 6 : int main(int argc, char** argv) 7 : { 8 : logger gui("app.gui"); 9 : gui.stream() << "hey - I've done something GUIsh" << std::endl; 10: 11: return 0; 12: } However I get a compile error saying: BuildTest\Main.cpp(9): error C2676: binary '<<' : 'boost::logging::logger_stream' does not define this operator or a conversion to a type acceptable to the predefined operator Any ideas? Thanks, David

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[program_options] bug or not... change proposal
by Ovanes Markarian 10 Aug '06

10 Aug '06

In my former post I wrote about assertions in program_options library... Since nobody answered I had to debug some boost::code. As I found out, current assertion of po relies in the following: in the function format_paragraph (option_description.cpp:365) is written: //... if (line_begin + (line_length - indent) > par_end) //... line_begin is of type std::string::const_iterator; line_length - indent is 51 in the last line only one word is written, which is shorter then 51 characters. By adding 51 to an iterator an assertion check is made, that the addition will produce an iterator out of string bounds. I know that iterators should behave like pointers, but in this case it is impossible to debug. Would be nice if some of boost developers decide to make a workaround. I will fix it locally. With Kind Regards, Ovanes Markarian

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Re: [Boost-users] Cross-compiling boost
by Hughes, James 10 Aug '06

10 Aug '06

Hi, I cross compile to an Arm platform with the following... bjam "-sGCC_ROOT_DIRECTORY=/opt/montavista/mobilinux/devkit/arm/iwmmxt_le" "-sGCC=iwmmxt_le-gcc" "-sGXX=iwmmxt_le-g++" stage This builds the libs to a stage folder, rather than installing them. You can then copy to the target from there. I used to get a hat load of compile faults, but it turned out to be a fault with the Montavista GCC compiler - fixed now. James > -----Original Message----- > From: boost-users-bounces(a)lists.boost.org > [mailto:boost-users-bounces@lists.boost.org] On Behalf Of > Pfligersdorffer, Christian > Sent: 09 August 2006 14:51 > To: Boost-Users (E-Mail) > Subject: [Boost-users] Cross-compiling boost > > Dear boost-community, > > has anyone experience in cross-compiling boost? I tried to > build the whole thing using eldk ppc_6xx-gcc for linux @ > power pc, doing the build process on linux @ x86. It > generated object code for x86 whatever I did. Thought about > writing a toolset but I don't understand a single bit of what > happens in gcc-tools.jam :-( > > In effect I'd need the possibility to add a prefix for the > gcc-tools, because all the gcc, g++, ld etc. are named > ppc_6xx-gcc, ppc_6xx-g++, ppc_6xx-ld instead. And I'd want to > specify PPC as the target platform while building on a > different (x86) platform. > > Hoping that someone has an idea. > Yours, Christian Pfligersdorffer > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users > This message (including any attachments) contains confidential and/or proprietary information intended only for the addressee. Any unauthorized disclosure, copying, distribution or reliance on the contents of this information is strictly prohibited and may constitute a violation of law. If you are not the intended recipient, please notify the sender immediately by responding to this e-mail, and delete the message from your system. If you have any questions about this e-mail please notify the sender immediately.

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Cross-compiling boost
by Pfligersdorffer, Christian 10 Aug '06

10 Aug '06

Dear boost-community, has anyone experience in cross-compiling boost? I tried to build the whole thing using eldk ppc_6xx-gcc for linux @ power pc, doing the build process on linux @ x86. It generated object code for x86 whatever I did. Thought about writing a toolset but I don't understand a single bit of what happens in gcc-tools.jam :-( In effect I'd need the possibility to add a prefix for the gcc-tools, because all the gcc, g++, ld etc. are named ppc_6xx-gcc, ppc_6xx-g++, ppc_6xx-ld instead. And I'd want to specify PPC as the target platform while building on a different (x86) platform. Hoping that someone has an idea. Yours, Christian Pfligersdorffer

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