September 2003 - Boost-users - lists.preview.boost.org

[bgl] how to reverse a graphvizDigraph?
by Jeremie Leguay 24 Sep '03

24 Sep '03

Hi! I would like to reverse all the edges of a graphviz graph but the structure of this kind of graph doesn't seems to fit with the one use by the reverse_graph functionalities. Am I true or did I forget something? Here is the code that doesnt work: GraphvizDigraph g; read_graphviz("datas",g); typedef reverse_graph<GraphvizDigraph> ReverseGraphType; ReverseGraphType gr(g); print_graph(gr, get(vertex_index, gr)); //if I remove this line, it works! More generally, I would like to inverse the graph with keeping the same indexes on the vertices. Do you have ideas? best regards /Jeremie Leguay

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regex problem
by Scott McCaskill 24 Sep '03

24 Sep '03

I seem to be having some trouble with the regex library: #include <boost/regex.hpp> #include <cassert> #include <iostream> int main(int argc, char* argv[]) { using namespace boost; cmatch what; assert(regex_match("foo: bar", what, regex("([\\w]+):[\\s]*(.*)"))); assert(what.size() == 3); assert(what[1].matched); assert(what[2].matched); assert(std::string("foo") == std::string(what[1])); std::cout << std::string(what[2]) << "\n"; assert(std::string("bar") == std::string(what[2])); // fails return 0; } The last assert always fails, because regex::match insists on including the space after the ":" in the second match result, which seems wrong to me. I've tried giving various different combinations of flags to the regex ctor, although from what I can tell from the documentation the default flags should work. This is with VC7 and boost 1.30.2. For comparison, perl (5.6.1) does not seem to have this problem, as the following script illustrates: #!/usr/bin/perl print "matches: <$1> <$2>\n" if ('foo: bar' =~ /([\w]+):[\s]*(.*)/); Is there any way to get the behavior I want? Thanks, Scott McCaskill

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Regex and stream processing
by Yaroslav Govorunov 23 Sep '03

23 Sep '03

Hello everybody and especially Dr John Maddock :) ! First of all I wish to thank all developers for this amazing product. I come here to get an advice and here is my problem: We have a stream of text data (actually it is a chunked response of a webserver, but it might be a file or something...) The data size may be very large and we need to do some find/replace in this stream using regular expressions. It is not possible to load entire stream into the memory. I'm not even hope that Regex++ could work with such kind of streams, but maybe someone can suggest me a solution to this problem? With best regards, Yaroslav Govorunov, E-mail: slov(a)rsdn.ru http://www.rsdn.ru http://www.isapirewrite.com

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Preprocessor Library question
by Eric Robert 23 Sep '03

23 Sep '03

Hi, Maybe somebody can help me here. I'm just trying to understand what's going on with the FOR code. It goes something like this (I expanded the general include and stripped some code for clarity) : # define BOOST_PP_FOR BOOST_PP_CAT(BOOST_PP_FOR_, BOOST_PP_AUTO_REC(BOOST_PP_FOR_P, 256)) # # define BOOST_PP_FOR_P(n) BOOST_PP_CAT(BOOST_PP_FOR_CHECK_, BOOST_PP_FOR_ ## n(1, BOOST_PP_FOR_SR_P, BOOST_PP_FOR_SR_O, BOOST_PP_FOR_SR_M)) # # define BOOST_PP_FOR_SR_P(r, s) s # define BOOST_PP_FOR_SR_O(r, s) 0 # define BOOST_PP_FOR_SR_M(r, s) BOOST_PP_NIL # # define BOOST_PP_FOR_1(s, p, o, m) BOOST_PP_FOR_1_C(BOOST_PP_BOOL(p(2, s)), s, p, o, m) # define BOOST_PP_FOR_2(s, p, o, m) BOOST_PP_FOR_2_C(BOOST_PP_BOOL(p(3, s)), s, p, o, m) # define BOOST_PP_FOR_3(s, p, o, m) BOOST_PP_FOR_3_C(BOOST_PP_BOOL(p(4, s)), s, p, o, m) # define BOOST_PP_FOR_4(s, p, o, m) BOOST_PP_FOR_4_C(BOOST_PP_BOOL(p(5, s)), s, p, o, m) # define BOOST_PP_FOR_5(s, p, o, m) BOOST_PP_FOR_5_C(BOOST_PP_BOOL(p(6, s)), s, p, o, m) # # // # // EXTENDED include <boost/preprocessor/repetition/detail/for.hpp> # # define BOOST_PP_FOR_1(s, p, o, m) BOOST_PP_FOR_1_C(BOOST_PP_BOOL(p(2, s)), s, p, o, m) # define BOOST_PP_FOR_2(s, p, o, m) BOOST_PP_FOR_2_C(BOOST_PP_BOOL(p(3, s)), s, p, o, m) # define BOOST_PP_FOR_3(s, p, o, m) BOOST_PP_FOR_3_C(BOOST_PP_BOOL(p(4, s)), s, p, o, m) # define BOOST_PP_FOR_4(s, p, o, m) BOOST_PP_FOR_4_C(BOOST_PP_BOOL(p(5, s)), s, p, o, m) # define BOOST_PP_FOR_5(s, p, o, m) BOOST_PP_FOR_5_C(BOOST_PP_BOOL(p(6, s)), s, p, o, m) # # define BOOST_PP_FOR_1_C(c, s, p, o, m) BOOST_PP_IIF(c, m, BOOST_PP_TUPLE_EAT_2)(2, s) BOOST_PP_IIF(c, BOOST_PP_FOR_2, BOOST_PP_TUPLE_EAT_4)(BOOST_PP_EXPR_IIF(c, o)(2, s), p, o, m) # define BOOST_PP_FOR_2_C(c, s, p, o, m) BOOST_PP_IIF(c, m, BOOST_PP_TUPLE_EAT_2)(3, s) BOOST_PP_IIF(c, BOOST_PP_FOR_3, BOOST_PP_TUPLE_EAT_4)(BOOST_PP_EXPR_IIF(c, o)(3, s), p, o, m) # define BOOST_PP_FOR_3_C(c, s, p, o, m) BOOST_PP_IIF(c, m, BOOST_PP_TUPLE_EAT_2)(4, s) BOOST_PP_IIF(c, BOOST_PP_FOR_4, BOOST_PP_TUPLE_EAT_4)(BOOST_PP_EXPR_IIF(c, o)(4, s), p, o, m) # define BOOST_PP_FOR_4_C(c, s, p, o, m) BOOST_PP_IIF(c, m, BOOST_PP_TUPLE_EAT_2)(5, s) BOOST_PP_IIF(c, BOOST_PP_FOR_5, BOOST_PP_TUPLE_EAT_4)(BOOST_PP_EXPR_IIF(c, o)(5, s), p, o, m) # define BOOST_PP_FOR_5_C(c, s, p, o, m) BOOST_PP_IIF(c, m, BOOST_PP_TUPLE_EAT_2)(6, s) BOOST_PP_IIF(c, BOOST_PP_FOR_6, BOOST_PP_TUPLE_EAT_4)(BOOST_PP_EXPR_IIF(c, o)(6, s), p, o, m) # # define BOOST_PP_FOR_257(s, p, o, m) BOOST_PP_ERROR(0x0002) # # define BOOST_PP_FOR_CHECK_BOOST_PP_NIL 1 # # define BOOST_PP_FOR_CHECK_BOOST_PP_FOR_1(s, p, o, m) 0 # define BOOST_PP_FOR_CHECK_BOOST_PP_FOR_2(s, p, o, m) 0 # define BOOST_PP_FOR_CHECK_BOOST_PP_FOR_3(s, p, o, m) 0 # define BOOST_PP_FOR_CHECK_BOOST_PP_FOR_4(s, p, o, m) 0 # define BOOST_PP_FOR_CHECK_BOOST_PP_FOR_5(s, p, o, m) 0 Now, I'm trying to understand how it works. I don't understand why FOR isn't a shortcut for FOR_1. The only reason I see is the FOR_CHECK test but I can't seems to understand how it works. Anyone ? Eric Robert

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regex compile problem with vc6 and stlport
by Sven Olsen 23 Sep '03

23 Sep '03

I am using MSVC6 (sp5) with STLport v4.5.3 and attempting to compile boost::regex v3.31, as far as I know these are the latest versions/updates. I dutifully followed the installation instructions, but `nmake -fvc6-stlport.mak` died with the error: ../src/cpp_regex_traits.cpp(662) : error C2660: 'isspace' function does not take 2 parameters By building the files in the IDE, I was able to figure out why the isspace error happens: there is a global scope isspace() defined in ctype.h. The isspace problem can be fixed by defining BOOST_REGEX_STD to be std:: (in other words, getting rid of the old STLport isspace workaround). But with that done, I now get a number of linking errors when I try to build the library using nmake (though I have been able to compile .dlls via the IDE). By manually adding stlport_vc6.lib to the list of linked libraries, I can get rid of all reported linking errors, but the dll's are still failing to compile. Has anyone else using STLport v4.5.3 and regex 3.31 (boost dist 1.30.2) gotten the library to compile under MSVC6? At this point I may try compiling the dlls by hand through the IDE, but it seems like there ought to be a way to get nmake working... Thanks, Sven PS- I should probably admit that this is my first time trying to compile regex using STLport, so it's quite possible that there is some silly little thing that I am doing wrong... I have tried setting the include and lib paths both manually and using the STLPORT_PATH environment variable (C:\STLport-4.5.3 in my case), and I get the same results either way.

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Icompatibility between MS cl preprocessor and boost macro constructs
by m.doppler＠icoserve.com 22 Sep '03

22 Sep '03

Hi, the header files boost/iterator_adaptors.hpp and boost/regex/v3/instances.hpp contain macro constructs that are icompatible with the Microsoft compiler cl when using them in a source file, preprocessing the source to a another source file and afterwards compiling the preprocessed source file. For iterator_adaptors.hpp, cl version 13.00 is affected, for instances.hpp cl 13.00 and 13.10. The problem can be reproduced by compiling the following simple source file (test.cpp) in the base boost directory (boost-1.30.2): #include "boost/iterator_adaptors.hpp" #include "boost/regex.hpp" int main(void) { return 0; } The commandline to preprocess the file is: cl /TP /GX /EHsc /Zc:wchar_t /Zc:forScope /c /I. /P test.cpp The commandline to compile the previously preprocessed file is: cl /TP /GX /EHsc /Zc:wchar_t /Zc:forScope /c /I. test.i Note that when directly compiling the same test program using the following commandline the problem disappears: cl /TP /GX /EHsc /Zc:wchar_t /Zc:forScope /c /I. test.cpp One might expect that the last command line should produce the same result as the first two, but unfortunately this is not the case. I have attached a patch file that solves the icompatibility with the preprocessor by incorporating the following changes: - In instances.hpp the patch adds single spaces between the BOOST_DEFAULT_ALLOCATOR and the end of some template declarations. - In iterator_adaptors.hpp the conditional BOOST_WORKAROUND macros are refactored from inside the template declarations of indirect_iterator_generator and indirect_iterator_pair_generator to the front of them by duplicating the template struct definitions minus the BOOST_WORKAROUND code in the else branch of the conditional macro. In case you wonder why we need to preprocess the source file into a seperate file before compiling it: This is required to use distcc (http://distcc.samba.org) with Microsofts cl. Is there a chance this patch gets accepted for the next boost version? Michael --- michael doppler ----------------------------------- developer icoserve it gmbh innrain 98, 6020 innsbruck tel: +43 - 512 - 567622 - 250 fax: +43 - 512 - 567622 - 111 web: www.icoserve.com email: m.doppler(a)icoserve.com ---------------------------------------------------------------

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boost::TokenizerFunction
by Zenaan Harkness 21 Sep '03

21 Sep '03

TokenizerFunction "Expression Semantics" table (documentation - eg. on debian: /usr/share/doc/libboost-doc/HTML/libs/tokenizer/index.htm), states that "tok is constructed", as part of "Precondition". However I note two things: 1: on looking at the source code for the provided example functions, each constructs a Token as it's first (or second) line of code in the call to operator(). 2: the "Semantics" says "The return value [bool] indicates whether a new token was found in the sequence". If there is no token available (eg. we are already at end of stream(/string) and will return false) why waste effort constructing storage for a token? Why does the doco say that the token must be constructed as a precondition? Is the code wrong, or the doco - ie. should my custom function construct a new (empty) token, or follow doco and have user construct one? It would seem potentially more efficient for the user to construct one, as they may be reused. I am trying to use (my own custom) function directly, in a for loop. Why would I use tokenizer class to wrap it? There is no example on using a function directly, thus these string of questions which I would like some answers on. The documentation for TokenizerFunction doesn't seem to have a proper doxygen-like api description - at least not on my local debian installation. So I have to revert to the source. As I'm a newbie, it is requiring quite a bit of going back and forth to try and figure it all out - eg., should I use a tokenizer (container), token_iterator, or just for-loop on a specific (custom) tokenizer function?? Finally, as I've been trying to figure out how to write my own TokenizerFunction. Delving into the code for the example TFs has eventually led me there, but a simpler example in the documentation would be very useful for other newbies, I'm sure. - I know, I should post the code. Well, I'm not done yet, and I'm implementing a function I need specifically, as opposed to just for learning or doco, but perhaps later in the week I can send something along if no one beats me to it. Once I understand it all a bit better. Simple one-hit functions can be a good way to learn how to code what you need (ie. not templatized). A progression from a one-hit to a templatized version would be ideal for learning. TIA Zen -- Mr Zenaan Harkness Phone +61 (0)412 166 990 Please respect the confidentiality of this email.

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Q: exceptions and -fPIC
by Andrey Nechypurenko 19 Sep '03

19 Sep '03

Hi, I am on the following platform: Linux 2.6.0-test5 #11 Wed Sep 10 20:28:31 CEST 2003 i686 unknown Reading specs from /usr/lib/gcc-lib/i386-slackware-linux/3.2.2/specs Configured with: ../gcc-3.2.2/configure --prefix=/usr --enable-shared --enable-threads=posix --enable-__cxa_atexit --disable-checking --with-gnu-ld --verbose --target=i386-slackware-linux --host=i386-slackware-linux Thread model: posix gcc version 3.2.2 Boost version 1.30.2 compiled with: bjam "-sTOOLS=gcc" I have a question regarding the following boost::filesystem use case: try { for(fs::directory_iterator dir_itr(full_path); dir_itr != end_iter; ++dir_itr ) { // use dir_itr } } catch(const std::exception &ex) { std::cout << ex.what() << std::endl; } In case of full_path pointed to the directory without read permissions the corresponding exception is thrown and catched in the catch block. My problem is that if I compile my application with -fPIC option, I am unable to catch the exception anymore and the program is simply aborted. I need to use -fPIC because of other library which has own build system and if I follow suggested guidlines for Makefile, I get -fPIC automatically. I would verry appreciate if somebody could tell me are there any ways to make the code mentioned above work when it is compiled with -fPIC? Should I recompile boost with -fPIC? If yes, what is the right place to set this parameter? BTW how it is supposed to write a shared library which includes boost code? As I understand, than my code must be compiled with -fPIC... Thanks, Andrey. P.S. Here is example I am using and the makefile: // ttt.cpp #include <iostream> #include <boost/filesystem/operations.hpp> #include <boost/filesystem/path.hpp> namespace fs = boost::filesystem; int main(int argc, char **argv) { try { fs::path full_path = fs::system_complete(fs::path(argv[1], fs::native)); fs::directory_iterator end_iter; for(fs::directory_iterator dir_itr(full_path); dir_itr != end_iter; ++dir_itr ) { std::cout << dir_itr->leaf() << std::endl; } } catch(const std::exception &ex) { std::cout << ex.what() << std::endl; } return 0; } Makefile: CPPFLAGS := -I/usr/local/src/boost LDFLAGS := -L/usr/local/src/boost/libs/filesystem/build/bin/libboost_filesystem.a/gcc/debug/runtime-link-dynamic/ LIBS := $(LIBS) -lboost_filesystem ttt: ttt.cpp c++ $(CPPFLAGS) -g -ftemplate-depth-128 -fPIC -Wall $(LDFLAGS) -o $@ ttt.cpp $(LIBS) __________________________________ Do you Yahoo!? Yahoo! SiteBuilder - Free, easy-to-use web site design software http://sitebuilder.yahoo.com

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Spirit library - Problem with the copy constructor of the class rule<> ?
by fritz.birnbacher＠t-online.de 18 Sep '03

18 Sep '03

Hello, I am new in using boost and I played a little bit with the spirit library. I tried following code using MSVC 7.1 and boost 1.30.2 #include"stdafx.h" #include<spirit.hpp> using namespace boost::spirit; rule<> GetRule() { rule<> r = anychar_p; return r; } void Parse1() { char s[] = "ABCD"; parse(s, GetRule()); } void Parse2() { rule<> r = anychar_p; char s[] = "ABCD"; parse(s,r); } int _tmain() { Parse1(); return 0; } Parse1() throws an exception (access violation) Parse2() works correct. Is it a compiler problem or a problem in spirit or my problem ? Thanks

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may it change ?
by maxch 17 Sep '03

17 Sep '03

Hi All, I am a new user of Boost. but when I look the source of Boost, I found that almost all the implementations is put in head files together, not as usual to put into CPP file. I know, it must be intended, however, could it possible to move the implementations into cpp file in future? Sorry if this question has been posted. Thanks!

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