November 2004 - Boost-users

boost::shared_ptr and stl algorithms
by Bill Eidson 15 Apr '05

15 Apr '05

std::vector< boost::shared_ptr<T> > TVec; I want to write a function object to run std::for_each. to do somework against members of T and accumulate results in functor. My attempts have failed in VC7 with memory errors in my operator() method. struct fo { bool operator()( boost::shared_ptr<T>& t ) { return true; } }; Thanks in advance bille

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Will libraries built on WinNT run on Win98? (MinGW)
by Reed Hedges 31 Mar '05

31 Mar '05

I know that Win98 is not really supported, but is there any chance that libraries (specifically thread and regex) that were build on WinNT using MinGW work on Win98 (in MinGW)? My guess is no, but has anyone tried it? thanks reed

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Bug in lexical_cast<> with doubles
by Leon Raj 29 Jan '05

29 Jan '05

I think I've found a bug in the boost::lexical_cast<> library (v1.31.0) on WinXP SP1, MSVC 6.0 (sp5) and MSVC.NET 2003. --- Start code snippet --- #include <boost/lexical_cast.hpp> #include <iostream> int main( int argc, char* argv[] ) { double dMax = = std::numeric_limits< double >::max(); // On a Win32 x86 system, dMax is now 1.7976931348623157e+308 // This is successful and strMax is "1.797693134862316e+308" std::string strMax = boost::lexical_cast< std::string >( dMax ); try { double newDMax = boost::lexical_cast< double >( strMax ); std::cout << "Successfuly" << std::endl; } catch ( boost::bad_lexical_cast& ) { std::cout << "Failed to cast" << std::endl; } // On a Win32 x86 system, this always fails, // because (I think) strMax overflows a double, // because 1.7976931348623157e+308 is *rounded UP* // to 1.797693134862316e+308, which cannot be // represented by a double } --- End code snippet --- ----------------------------------------------------- Leon Raj Senior Engineer Invetech Pty. Ltd. Phone: +61 3 9211 7000 (Switchboard) +61 3 9211 7938 (DDI) leon.raj(a)invetech.com.au IMPORTANT - This e-mail and any attachments may be confidential. Any retransmissions, dissemination or other use of these materials by persons or entities other than the intended recipient is prohibited. If received in error, please contact us and delete all copies. Before opening or using attachments, check them for viruses and defects. Our liability is limited to resupplying any affected attachments. [Any representations or opinions expressed in this e-mail are those of the individual sender, and not necessarily those of Vision Systems Limited].

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boost::regex partial matches
by L.P. Mergen 31 Dec '04

31 Dec '04

Hello, I apologise in advance if this question is not direct to the right mailinglist, but this was the best I could find. The IRC channel also seems very quite... :) I am currently experimenting with the boost::regex library, and so far it seems to do just the thing I need. However, when I have a regex "[0-9]+[a-zA-Z]+" And want to match this against the string "42foo 42bar" It returns false. This is (as far as I can see) due to the library not taking partial matches too, even when I set the boost::match_partial and boost::match_any flags (which, according to my interpretation, should be doing the trick). Here is my statement: bool success = boost::regex_match(subject->c_str(), returns, expression, boost::match_partial | boost::match_any); I hope anyone has an idea what might be the problem here. Thanks in advance! :) Grt, Leon Mergen

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graphviz compile problem
by Jean Utke 15 Dec '04

15 Dec '04

I am running into a problem compiling code that uses write_graphviz which used to work e.g. for gcc 3.3 and boost versions prior to 1.31. As I am trying to move forward I am testing different gcc and boost versions. Here is the example code: ---------------------------------------------------------------- #include "boost/graph/adjacency_list.hpp" #include "boost/graph/graphviz.hpp" class BoostVertexContentType { public: enum { num=100 }; typedef boost::vertex_property_tag kind; }; class BoostEdgeContentType { public: enum { num=101 }; typedef boost::edge_property_tag kind; }; int main(void) { boost::adjacency_list< boost::listS, boost::listS, boost::bidirectionalS, boost::property<BoostVertexContentType, int>, boost::property<BoostEdgeContentType, int> > b; std::ofstream anOutFileStream; anOutFileStream.open("test.dot",std::ios::out); boost::write_graphviz(anOutFileStream, b); anOutFileStream.close(); } ----------------------------------------------------------------- This compiles ok with gcc 3.3 and boost 1.30.0 / 1.30.2 It does not compile with gcc 3.3/3.4.3 and boost 1.31/1.32 basically complaining about: boost_1_32_0/boost/graph/graphviz.hpp:269: error: no match for `std::basic_ostream<char, std::char_traits<char> >& << const boost::detail::error_property_not_found&' operator My target right now is to use gcc 3.4.3 with boost 1.32. Before I spend time searching for a workaround I hope that somebody has seen this and that there is an easy solution. Thanks, Jean

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Boost format library Segmentation fault with Intel 8.1
by Filipe Sousa 08 Dec '04

08 Dec '04

Hi! I get a segmentation fault with Intel compiler 8.1 using the fallowing code #include <boost/format.hpp> #include <iostream> int main() { std::cout << boost::format("writing %1%, x=%2% : %3%-th try") % "toto" % 40.23 % 50 << std::endl; return 0; } (idb) bt #0 0x0804aba8 in ctype<char>::is (this=0x41016b50, __m=2048, __c=49 '1') at ctype_inline.h:40 #1 0x08051d55 in std::isdigit (__c=49 '1', __loc=& { ... }) at locale_facets.h:4528 #2 0x0805517f in boost::io::detail::wrap_isdigit (c=49 '1', os=& { ... }) at parsing.hpp:36 #3 0x0805509b in boost::io::detail::wrap_scan_notdigit (beg= { ... }, end= { ... }, os=& { ... }) at parsing.hpp:46 #4 0x08054f7b in boost::io::detail::upper_bound_from_fstring (buf=& { ... }, arg_mark=37 '%', os=& { ... }, exceptions=-1 '\377') at parsing.hpp:351 #5 0x0804d33a in basic_format<char,std::char_traits<char> >::parse (this=0xbffff480, buf=& { ... }) at parsing.hpp:377 #6 0x0804ceab in basic_format<char,std::char_traits<char> >::basic_format (this=0xbffff480, str=0x80572a8 "writing %1%, x=%2% : %3%-th try") at format_implementation.hpp:37 #7 0x0804d02c in basic_format<char,std::char_traits<char> >::basic_format (this=0xbffff480, =<no value>) at format_implementation.hpp:38 #8 0x0804a41c in main () at test.cc:5 #9 0x4102e7f8 The same code works perfectly with gcc-3.4.2 under linux. Is this a bug in boost format library or a Intel compiler problem? My system: Debian, boost-1.31.0, gcc-3.4.2, Intel compiler 8.1 -- Filipe Sousa

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iterator_adaptor: disguise iterator as const_iterator?
by Martin Wartens 03 Dec '04

03 Dec '04

Hi all, I am trying to disguise a std container non-const iterator as a const_iterator. My guess is that iterator_adaptor could be useful for this, but I can't figure it out myself. I am trying to solve an old problem with the standard library, which is that you can't convert a const_iterator into an iterator. [There are two "solutions" to that problem, one uses distance and is expensive, the other one does a brutal conversion on bitlevel which breaks for several std implementations.] My use case: I have written a wrapper class mymap for std::map. I only want to give map::const_iterators to the users of this class. If the user wants to erase an element from the map, he must pass a const_iterator back to the wrapper class and call "mymap::erase(const_iterator)". The problem is that mymap has no way to convert the const_iterator into an iterator to call "map::erase(iterator)" in turn [there is no "map::erase(const_iterator)"]. So my idea was to write a iterator_adaptor for iterator that lets it behave like a const_iterator. Unfortunately I didn't get very far. I have to say that the documentation was not of much help to me. There are lots of complicated implementation details but only small examples. So any help is appreciated. How can I solve my problem? Side note: In the following code sample, iterator_adaptor accidentally turns a const_iterator into a non-const iterator. (Seemingly, some bit-level casting is done somewhere). Is this a bug? #include <boost/iterator/iterator_adaptor.hpp> #include <map> template <class Value> class node_iter :public boost::iterator_adaptor<node_iter<Value>, Value> { public: node_iter() : node_iter::iterator_adaptor_(0) {} node_iter(Value p) : node_iter::iterator_adaptor_(p) {} }; int main() { typedef std::map<int, int> mymap_type; mymap_type testmap; node_iter<mymap_type::const_iterator> ni(testmap.begin()); ni->second = 42; //this works, not a const_iterator anymore } ___________________________________________________________________________ Die einen haben es, die anderen werden es! http://my-mail.ch/?redirect=9905 So macht schenken richtig Freude! Schenken und Helfen mit World Vision! http://www.my-mail.ch/?redirect=1958

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Q: W4003 with vc7 boost=1.32 in date_time lib
by Dan Dimerman 02 Dec '04

02 Dec '04

Hello, I just wanted to see if there are others getting this warning in VC7 with Boost 1.32, or it's just me doing something wrong with the #include order or forgetting a #define. The warning reads: C:\Boost\include\boost-1_32\boost\date_time\gregorian\greg_facet.hpp(293) : warning C4003: not enough actual parameters for macro 'max' thanks for any help... Dan --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com) Version: 6.0.802 / Virus Database: 545 - Release Date: 26-Nov-04

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newbie boost sample compile program
by Brian Gaber 01 Dec '04

01 Dec '04

I have installed boost on both Windows and AIX and get the same problem when I try to compile the simple_ls.cpp program that boost provides. In AIX the boost hpp files get installed in /usr/local/include/boost-1_32/boost/... I created /usr/local/include/boost/... with this command: ln -s /usr/local/include/boost-1_32/boost /usr/local/include/boost In Windows the boost hpp files get installed C:\boost-1_32\boost\... In AIX when I try to compile simple_ls.cpp I get the following: "/usr/local/include/boost/filesystem/operations.hpp", line 18.10: 1540-0836 (S) The #include file <boost/filesystem/path.hpp> is not found. "/usr/local/include/boost/filesystem/operations.hpp", line 19.10: 1540-0836 (S) The #include file <boost/shared_ptr.hpp> is not found. "/usr/local/include/boost/filesystem/operations.hpp", line 21.10: 1540-0836 (S) The #include file <boost/iterator.hpp> is not found. "/usr/local/include/boost/filesystem/operations.hpp", line 22.10: 1540-0836 (S) The #include file <boost/cstdint.hpp> is not found. "/usr/local/include/boost/filesystem/operations.hpp", line 27.10: 1540-0836 (S) The #include file <boost/config/abi_prefix.hpp> is not found. "/usr/local/include/boost/filesystem/operations.hpp", line 149.10: 1540-0836 (S) The #include file <boost/config/abi_suffix.hpp> is not found. my simple_ls.cpp currently has the following include statements: #include "/usr/local/include/boost/filesystem/operations.hpp" #include "/usr/local/include/boost/filesystem/path.hpp" #include <iostream> simple_ls.cpp came with the following include statements which generate similar errors to those above: #include "boost/filesystem/operations.hpp" #include "boost/filesystem/path.hpp" #include <iostream> MS Visual C++ 6 generates the following similar error when attempting to compile simple_ls.cpp c:\boost\include\boost-1_32\boost\filesystem\operations.hpp(18) : fatal error C1083: Cannot open include file: 'boost/filesystem/path.hpp': No such file or directory Thanks for any tips.

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Format Library - Asterisk Support
by Barak Simon 01 Dec '04

01 Dec '04

Hi, I have noticed that the format library does not support at present the printf asterisk for providing dynamic width as an extra parameter. Unfortunately my users need to use this widely and I would really hate to revert back to a non-typesafe solution. a. Are there any plans to support it in near future? b. If not, is there an easy way to add that to parsing.hpp, parse_printf_directive method, parse_width & parse_precision sections? currently the asterisk is ignored, and the library throws an exception thinking it has an extra parameter. c. Is there any workaround I miss which may give me the same expected result of providing say "%*s, width, charPtr" ? (I have 'width' and a non-null-terminated char pointer and need to construct the correct string from them without doing unnecessary copying...) Many thanks, Barak ________________________ Barak Simon GED IT Core Platform Deutsche Bank 190 George St. Sydney, 2000 Phone +61 2 925 85070 Fax +61 2 925 95050 -- This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden.

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