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remove_pointer
by Leo Landa 05 Oct '03

05 Oct '03

Good day to everyone, I am trying to find a portable enough implementation of remove_pointer (MSVC 6, MSVC 7.1, G++ 2.95.3, G++ 2.96). The "usual" template technique relies on partial template specialization, which MSVC 6.0 does not support. As far as I can tell, Boost's version of remove_pointer is a little bit of a "cheat" - i.e. it becomes predefined only for primitive types. Am I right about that? I'm a bit of a newb in these parts of London ;-) If this is true, then I'm screwed - and I can't convert a generic pointer type to the pointee type. If it is not true, then what is the technique? Leo. P.S. Just in case - I know how to figure out _whether_ the type is a pointer, and now just trying to strip it.

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iterators
by Witz 05 Oct '03

05 Oct '03

Hi, I would like to raise a couple of points about the iterator adaptors. Firstly, is it really necessary to have the predicate as part of the template specification for the filter_iterator? Surely it can be assumed that it will always be convertible to boost::function<bool (const value_type&)> ? Secondly, by allowing the return type of the function used by the transform_iterator to be a reference can we not use it to implement a more generic form of indirect_iterator? The code below gives a flavour of the idea. struct dereference { typedef int result_type; int* data_; dereference(int* data):data_(data){} int operator()(int i) const { return data_[i]; } }; int main() { int data[] = { 1,2,3,4,5,6,7,8 }; int keys[] = { 0,3,1,6,5,4,2,7 }; typedef boost::transform_iterator_generator<dereference, int*>::type indirect_iterator; indirect_iterator i(keys, dereference(data)), i_end(keys+8,dereference(data)); while(i != i_end) std::cout << *i++ << ' '; return 0; } The output is: 1 4 2 7 6 5 3 8 Witz

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boost library build consistency
by Thomas S. Urban 03 Oct '03

03 Oct '03

Is there any definition of how libraries are supposed to build? I've integrated the building of required boost libraries into the build system for our projects. There seems to be some inconsistency in what gets built and where it gets put. In particular, for the thread and regex libs, boost builds both shared and static versions of the libraries and puts them in a bin-stage subdirectory under the library build directory. However, for the filesystem library, only the static library gets built and the bin-stage/ directory is not used. Is there a standard behavior library developers are supposed to follow in this regard? Can I count on the bin-stage/ as a short-named location for the most recent build of any library? Are the boost or boost_filestsystem maintainers interested in the simple fix to the Jamfile to make that library behave like the other two I mentioned? Thanks Scott Urban

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parse error in format library
by Alan Stewart 03 Oct '03

03 Oct '03

I've been successfully using the tokenizer library for some time, and am very grateful for it. The format library looks very userful - I need to convert a bunch of old printf's to ostreams. However, in attempting to compile with gcc 2.96 I'm finding that there are many substitutions that need to be made, such as replacing "char_traits" with "basic_string". I'm using Boost 1.30.0 in production, but have also tried 1.30.2 with the same results. I see that the format library headers include the header file "boost/config.hpp". Is it likely that I have some sort of configuration error? Where do I find information on toolset compatabiliy for specific Boost libraries, since this one does not seem to be compatible with mine? -- D. Alan Stewart Senior Software Developer Layton Graphics, Inc. 155 Woolco Drive Marietta, GA 30065 Voice: 770/973-4312 Fax: 800/367-8192 http://www.layton-graphics.com

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Problem using Boost.thread : Class destructor called several times!
by Huck finn 02 Oct '03

02 Oct '03

Hi there, still a newbie question for you guys... I changed a bit the sample example from thread.cpp : here's the new code i'm trying: ----------------- boost::mutex io_mutex; // The iostreams are not guaranteed to be thread-safe! class FakeClass { public: FakeClass(int NewID):ID(NewID) { boost::mutex::scoped_lock scoped_lock(io_mutex); std::cout<<"FakeClass #"<<ID<<" says : "<<"I'm alive!"<<std::endl; } ~FakeClass() { boost::mutex::scoped_lock scoped_lock(io_mutex); std::cout<<"FakeClass #"<<ID<<" says : "<<"I'm being destroyed!"<<std::endl; } void operator()() { boost::mutex::scoped_lock scoped_lock(io_mutex); std::cout<<"Thread for FakeClass #"<<ID<<" has been started!"<<std::endl; } private: int ID; }; void main () { boost::thread_group group; FakeClass item1(1),item2(2); group.create_thread(item1); group.create_thread(item2); group.join_all(); std::cout<<" main ending..."<<std::endl; } ----------------------------- here's what I get when executing : FakeClass #1 says : I'm alive! FakeClass #2 says : I'm alive! FakeClass #1 says : I'm being destroyed! FakeClass #1 says : I'm being destroyed! FakeClass #1 says : I'm being destroyed! Thread for FakeClass #1 has been started! FakeClass #2 says : I'm being destroyed! FakeClass #1 says : I'm being destroyed! FakeClass #2 says : I'm being destroyed! FakeClass #2 says : I'm being destroyed! Thread for FakeClass #2 has been started! FakeClass #2 says : I'm being destroyed! main ending... FakeClass #2 says : I'm being destroyed! FakeClass #1 says : I'm being destroyed! Press any key to continue 1- I'm wondering why the destructor of my FakeClass is called 4 times for each items ??? 2- It says in the doc that the function that creates a thread "copies the function wrapped by threadfunc" and threadfunc would be in this case item1 and item2, does this means that the copy constructor is called every time a thread is created with an object? Thanks all! Simon _________________________________________________________________ MSN Messenger : discutez en direct avec vos amis ! http://messenger.fr.msn.ca/

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Problem with is_class and is_enum
by Romain Lerallut 02 Oct '03

02 Oct '03

In the following code, struct foo2 is mistakenly taken for an enum, which breaks is_class, which leads to some unfortunate problems in boost::python. Problem appears on both Boost 1.30.0 and a one-month old CVS checkout, using gcc 3.3.2 and 2.95 and Intel icc 7.1 for linux. I have tried specializing 'is_enum', setting it by hand to return 'false', but though it works for this simple case, it does no good when the call to is_enum is buried deep inside boost. I rely heavily on being able to do these implicit conversions for foo2, so if anyone has an idea on how to make this work, it would be great. Thanks in advance, Romain ---------------------------------------------------------------- #include <boost/type_traits/is_enum.hpp> #include <iostream> struct foo1 // this one is not detected as an enum { operator int() { return 0; } }; struct foo2 // this one *is* detected as an enum { template<typename T> operator T(){return 0;} }; int main() { std::cout<<boost::is_enum<int>::value<<"\n"; std::cout<<boost::is_enum<foo1>::value<<"\n"; std::cout<<boost::is_enum<foo2>::value<<"\n"; } -------------------------------------------------------------- Expected Result: 0 0 0 Actual Result: 0 0 1

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compilation on Win64 platform with MSVC7.1 for 64 bit
by bart.tanghe＠skynet.be 02 Oct '03

02 Oct '03

Hi, we're using Boost 1.30.0 with MSVC7.1 on a Win32 platform. Currently where working on a port to a Win64 platform using the MSVC7.1 for IA64 compiler. (13.10.2240.8 for IA64) I just compiled the code as is and unfortunately I encountered errors in boost headers. This probably is because of missing/bad defines for this 'unknown' platform in the config headers... I was wondering if somebody already tried to compile boost on a 64 bit platform, and if he/she succeeded? Or if there are known implementation details which would cause boost 'never' to work on 64 bit platforms? If there are no known 'showstoppers' then I suppose I'll have to go through the Boost Configuration Reference or should I look somewhere else? Thanks, Bart

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Compile Boost.thread libraries has a static library (.lib) with msvc 6 ?
by Huck finn 01 Oct '03

01 Oct '03

Hi everyone, I'm a total newbie to boost, but I've got to developp a project that could use some of the powerful boost libraries, so I'm trying to make a move in that way... Ok, most of the boost libraries I can build in a static way and create (.lib) files with Microsoft Visual Studio 6.0 for my partners to use . But I am having a problem doing the same thing with the Boost.Thread libraries... First question : Is it possible to build this librairy in a (.lib) file with msvc 6.0? I'm getting tons of warnings concerning "dllexport" problems, but the (.lib) are still created. I was wondering if someone could help me understanding/fixing the warning problems : warning C4275: non dll-interface class 'boost::noncopyable' used as base for dll-interface class 'boost::detail::condition_impl' c:\wrk\common\boost-1.30.2\boost\noncopyable.hpp(22) : see declaration of 'noncopyable' warning C4273: 'thread::thread' : inconsistent dll linkage. dllexport assumed. I really need to avoid using .dll in this project, so builing this static library is very important to me... Thanks in advance, Simon _________________________________________________________________ MSN Search, le moteur de recherche qui pense comme vous ! http://fr.ca.search.msn.com/

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bind and Constructor invocation?
by Jeff Flinn 30 Sep '03

30 Sep '03

I don't see any way to use bind to directly construct an object, other than calling a function that returns an object. Or am I missing something? Like something similar to Spirit::Phoenix construct_<>? This would avoid manually creating these factory functions. -- Jeff Flinn Applied Dynamics, International

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BGL runtime crash with g++ -O2 optimizer.
by Franck.Caron＠infineon.com 29 Sep '03

29 Sep '03

Hi all, I have a problem while compiling BGL with gcc 3.1.1 on solaris7 with the -O2 optimizer option. All is ok with -g (debug) but -O2 produce a crash at runtime Here is a code that reproduce the problem : #include <boost/graph/adjacency_list.hpp> #include <boost/graph/properties.hpp> #include <iostream> #include <string> using namespace std; using namespace boost; struct VertexPropertyTag { typedef vertex_property_tag kind; }; typedef property<VertexPropertyTag,string> VertexProp; typedef adjacency_list<setS,vecS,bidirectionalS,VertexProp> Graph; int main(){ Graph graph; graph_traits<Graph>::vertex_descriptor v1 = add_vertex(string("s1"),graph); graph_traits<Graph>::vertex_descriptor v2 = add_vertex(string("s2"),graph); add_edge(v1,v2,graph); graph_traits<Graph>::edge_iterator eIt,eItEnd; tie(eIt,eItEnd) = edges(graph); for(;eIt != eItEnd;++eIt){ cout << "->" << *eIt << endl; } return 0; } With g++ -Wall -pedantic -fPIC -g -c -o solaris7/gcc3.1/Main.o Main.cc -I. -I/opt/boost_1.30.2 g++ -fPIC -o solaris7/gcc3.1/testbug.exe solaris7/gcc3.1/Main.o -L /opt/boost_1.30.2/libs/gcc3.1/release/single-thread -R -Wl,-Bdynamic Here is the result : shell> solaris7/gcc3.1/testbug.exe ->(0,1) It is OK With g++ -Wall -pedantic -fPIC -O2 -c -o solaris7/gcc3.1/Main.o Main.cc -I. -I/opt/boost_1.30.2 g++ -fPIC -o solaris7/gcc3.1/testbug.exe solaris7/gcc3.1/Main.o -L /opt/boost_1.30.2/libs/gcc3.1/release/single-thread -R -Wl,-Bdynamic Here is the result : shell> solaris7/gcc3.1/testbug.exe ->(0,1) ->(0,0) Bus error (core dumped) Does anybody already had this ? Is it a bug in my code, in BGL or in gcc ? Thanks for the help. Franck

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Re: [Boost-users] Trying to get boost threads working under visual .NET
by John Maddock 29 Sep '03

29 Sep '03

> I'm trying to get the Boost thread library working under Microsoft .Net, > here is what I've done and the problems I'm seeing. > > I am currnetly using the regex lib and the date/time classes, which are > working. I now want to start creating threads so I follow the given > example, and started to get linker errors for xtime_get and > boost::thread::sleep. So I look around, and do the bjam -sTOOLS=msvc in > the appropriate threads directory and get no errors. It still won't > link. > I notice that the only boost*.lib files in my vc7\lib dir were from > boost_regexp, so I copy 4 files boost_thread(d).dll/lib into that > directory. I then explicitely add boost_threadd.lib into the project's > link. Ok, so now my application compiles AND links, but it wants > boost_threadd.dll when it executes. So I copy boost_threadd.dll into the > projects Debug directory wehre the .exe compiles to. Now when I run it, I > get a dialog box saying the application failed because > "boost_regex_vc7_mdid.dll" can not be loaded! the regex stuff was working > FINE and I don't think I did anyhting to change it. > > So can someone shed some light on this for me, please ? Why does it now > want the boost_regex dll? Thanks for any input.. if I've missed some > crucial documentation somewhere, sorry. If you changed your project build options from using one of the static C runtimes to using the dll runtime then that would be the problem, define BOOST_REGEX_STATIC_LINK when building if you want to static link to boost.regex. John. --------------------------------- Want to chat instantly with your online friends? Get the FREE Yahoo!Messenger

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regex and stream processing
by John Maddock 29 Sep '03

29 Sep '03

Message forwarded from Dave Gomboc: > 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? This is possible without much trouble _if_ the text strings you are trying to match will fit into main memory, even if all the data won't. Use a std::list as a buffer, so that deleting and inserting is inexpensive, and you don't have to perform copies and update iterators when reading in more input. Fill your (sliding window) buffer, then regex it, using the partial match feature whenever you have not already detected the end of the file. If a match occurs, any characters occuring before the match can be processed (serialized to disk, or whatever) and removed from the buffer. Repeat this looking for a match until you reach the end of current input. You'll either have "no match" or "partial match" at this point: remove non-matching characters (that could be all of them) at this point, then re-fill your buffer with more data and keep going. If you're just doing one substitution, that's fine, but if more, there are a few things to keep in mind. I have done over 60 distinct substitutions at a time on a stream of 0.1 gigabytes using this technique, and it works quite quickly. (I used a buffer that held about 1 million characters (2^20), but I also tested with buffers as small as 256 characters -- the strings I was matching were not large). Just read in data, process all the substitutions in order, write the data out and repeat. If you're doing multiple substitutions, you (of course) can't flush any data from memory until you've tried all the substitutions on the current region of interest. Also, for each later substituion, the current region of interest shrinks because you have to acknowledge partial matches from earlier subsitutions. For example, say that there is no partial match at the end of substituions 1 through 6 (there might have been full matches where substitution was performed, that's okay.) But substituion 7 has a partial match at the last five characters. Now, your region of interest for substitution 8 is five characters smaller, because you don't want to process those last five characters because substitution 7 might change them once you've read in more input. The order of your substituions is important if the outputs of some desired subsitutions overlap with the inputs of others. If you are not grokking my meaning, I can fish around for the source code. Perhaps it's easier to explain in code than in words, my code for the entire process is maybe 10 or 15 lines. An alternative is to try to do some streambuf hacking, but the above method was simpler and adequate for my purposes. Dave --------------------------------- Want to chat instantly with your online friends? Get the FREE Yahoo!Messenger

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regex problem
by John Maddock 29 Sep '03

29 Sep '03

> 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? This is the difference between perl and POSIX leftmost-longest matching rules showing itself (the next release will default to perl rules and do what you want, but of course that doesn't help you now), basically non-marked sections are neither greedy nor non-greedy under POSIX rules, so regex finds the match it does because it makes $2 further to the left than the alternative (without effecting the overall match). You can get the effect you want by making your expression more "precise": "([\\w]+):[\\s]*([^\\s].*)" for example, John. --------------------------------- Want to chat instantly with your online friends? Get the FREE Yahoo!Messenger

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Re: Implementation of my first template class
by Zenaan Harkness 29 Sep '03

29 Sep '03

Take 3: /** * A class providing a combination of an input stream * and an input iterator. * I use for convenience when processing a part-ascii, * part-binary stream. */ template<typename charT, typename traits = std::char_traits<charT> > class basic_istringtraverser : public std::basic_istringstream<charT, traits> { public: basic_istringtraverser(std::basic_string<charT> s) : std::basic_istringstream<charT, traits>(s) {} charT operator*() {return (charT)(rdbuf()->sgetc());} basic_istringtraverser& operator++() { rdbuf()->sbumpc(); return *this; } }; /** Specialization for char type. */ typedef basic_istringtraverser<char> istringtraverser;

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RE: [Boost-users] Base Pointer member functions failure
by Mark Loew 29 Sep '03

29 Sep '03

Excellent thanks. I see exactly what I was missing. Thanks for the help. Mark Loew, MCSD, MCSE Application Development Consultant Sagestone Consulting www.sagestone.com Grand Rapids, MI 616-954-9556 x149 Microsoft Gold Certified Partner mloew(a)sagestone.com -----Original Message----- From: Douglas Gregor [mailto:gregod@cs.rpi.edu] Sent: Saturday, September 27, 2003 1:58 PM To: Boost Users mailing list Subject: Re: [Boost-users] Base Pointer member functions failure On Friday 26 September 2003 06:38 pm, Mark Loew wrote: > Alright I am now functioning in my code. > > Now the hard part. Can you explain to me what I am missing. The _1 > states to use the first paramter in the first position. > > Doug mentioned that there is an implicit 'this' argument. That was Peter :) > So the bind is creating a function object > template<class S, class T, class A> > With the constructor of > somefunc( S (T::*p)(A) ); // declaring the pointer to the function > > then the operator is > operator( T *p, A x ) > and calls the func Right, so the function object has two parameters, the first (which corresponds to the implicit 'this' parameter) is of type T* and the second is of type A. When using bind, think of member function pointers as having an operator() like this one, and try to forget the ugly member pointer syntax. > So in the bind I was thinking that > Boost::bind( Base::CheckFunc, x ) > > I wrongly assumed that the T value was the variable passed in by the > find_if and the second parameter was the x my second variable on my > func. With bind(), no parameter is special, including the implicit object parameter. If we have: g = boost::bind(f, _1, x) then g(y) maps to: f(y, x) in our case, 'f' is an adaptor around a member function pointer, which ends up calling: y->*CheckFunc(x) Doug _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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Re: [Boost-users] istream U istream_iterator -> traverser
by Zenaan Harkness 28 Sep '03

28 Sep '03

Further thought: has anyone ever written (made available) something like <vstream> for streaming into and out of vectors (similar to <sstream>). Or perhaps <cstream> - generic container streaming in/out, with specializations for vector, etc. - or has such a thing just never been needed by anybody before? tia zen

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Trying to get boost threads working under visual .NET
by Brian Bowles 28 Sep '03

28 Sep '03

I'm trying to get the Boost thread library working under Microsoft .Net, here is what I've done and the problems I'm seeing. I am currnetly using the regex lib and the date/time classes, which are working. I now want to start creating threads so I follow the given example, and started to get linker errors for xtime_get and boost::thread::sleep. So I look around, and do the bjam -sTOOLS=msvc in the appropriate threads directory and get no errors. It still won't link. I notice that the only boost*.lib files in my vc7\lib dir were from boost_regexp, so I copy 4 files boost_thread(d).dll/lib into that directory. I then explicitely add boost_threadd.lib into the project's link. Ok, so now my application compiles AND links, but it wants boost_threadd.dll when it executes. So I copy boost_threadd.dll into the projects Debug directory wehre the .exe compiles to. Now when I run it, I get a dialog box saying the application failed because "boost_regex_vc7_mdid.dll" can not be loaded! the regex stuff was working FINE and I don't think I did anyhting to change it. So can someone shed some light on this for me, please ? Why does it now want the boost_regex dll? Thanks for any input.. if I've missed some crucial documentation somewhere, sorry.

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RE: [Boost-users] Base Pointer member functions failure
by Mark Loew 27 Sep '03

27 Sep '03

Alright I am now functioning in my code. Now the hard part. Can you explain to me what I am missing. The _1 states to use the first paramter in the first position. Doug mentioned that there is an implicit 'this' argument. So the bind is creating a function object template<class S, class T, class A> With the constructor of somefunc( S (T::*p)(A) ); // declaring the pointer to the function then the operator is operator( T *p, A x ) and calls the func So in the bind I was thinking that Boost::bind( Base::CheckFunc, x ) I wrongly assumed that the T value was the variable passed in by the find_if and the second parameter was the x my second variable on my func. What am I missing. I just don't want my code to work I want to know why. Makes reusing the thing much easier. Mark Loew, MCSD, MCSE Application Development Consultant Sagestone Consulting www.sagestone.com Grand Rapids, MI 616-954-9556 x149 Microsoft Gold Certified Partner mloew(a)sagestone.com -----Original Message----- From: Peter Dimov [mailto:pdimov@mmltd.net] Sent: Friday, September 26, 2003 6:11 PM To: Boost Users mailing list Subject: Re: [Boost-users] Base Pointer member functions failure Mark Loew wrote: > Okay, > > Call me stupid but I can't get this to work > > class Base > { > virtual const bool CheckFunc(const value& val ) const { return > true; } } [...] > std::find_if( vecBase.begin(), vecBase.end(), > boost::bind(Base::CheckFunc, aVal ) ); Try boost::bind(&Base::CheckFunc, _1, aVal) instead. Remember that a member function has an implicit 'this' argument. _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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Building boost threads with MinGW
by Jeremy Godfrey 27 Sep '03

27 Sep '03

Hi, When I build boost threads with bjam and MinGW, the resulting DLL is not dependent on mingwm10.dll like (as I understand things) all MinGW multithreaded binaries should be. This would indicate that the -mthreads compile/link option is not being used. Does anyone know how to fix this? Regards, Jeremy Godfrey --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com) Version: 6.0.520 / Virus Database: 318 - Release Date: 18/09/2003

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istream U istream_iterator -> traverser
by Zenaan Harkness 27 Sep '03

27 Sep '03

Sidestepping any ascii/binary issues for the moment, I am reading a part-binary, part-ascii file(s) and needing to process them (extract their data). I have need to read characters, as well as read in "binary" numbers, and print the whole lot out as ascii, with delimiters, etc (I use a mini-program/ format-string as a 'driver' to specify to my program how to process the input). I eventually realised (after converting my code back and fort between iterator style and istream style) that in fact I need both an istream and an input iterator (conveinence factor here). So firstly, I created both an istringstream, and an istream_iterator over that istringstream. Using either to .get or >> extract stuff from my string/stream would advance the underlying buffer, so things seem to work out well. I then decided to combine the two into a single class, which I can then "hide" implementation details or add functionality (eg. manipulators to specify byte-oirdering, endianness, etc), and still have one nice big interface of stream + iterator to get stuff from. My question is, why did this initial cut not compile: using namespace std; class istringtraverser : public istringstream, public istream_iterator<char> { public: istringtraverser(string s) : istringstream(s), istream_iterator<char>(*this) {} }; While this one DOES compile: using namespace std; class istringtraverser : public istringstream, public istream_iterator<char> { istringstream* miss; public: istringtraverser(string s) : istringstream(s), miss(this), istream_iterator<char>(*miss) {} }; And, how can I instantiate my traverser without it segfaulting? Eg., on my debian box, "istringtraverser st(some_string);" compiles but segfaults. Any insight appreciated, Zenaan PS I'm a Java programmer learning C++, finding out that C++ is more powerful/ featureful, yet some simple things (eg. uppercase a std::string, using std::transform with std::toupper) just do not work as expected. I can see why they now teach Java as a first language at Uni.

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Base Pointer member functions failure
by Mark Loew 26 Sep '03

26 Sep '03

Okay, Call me stupid but I can't get this to work class Base { virtual const bool CheckFunc(const value& val ) const { return true; } } class Derived1: public Base { } class Derived2: public Base { } // some where else in code Derived1 dev1; Derived2 dev2; vector<Base *> vecBase; vecBase.push_back( &dev1 ); vecBase.push_back( &dev2 ); value aVal; vec<Base *> std::find_if( vecBase.begin(), vecBase.end(), boost::bind( Base::CheckFunc, aVal ) ); I have tried a gazillion things a thought would work using mem_fun_ref and such. This ones get's me the closest I believe but I get a bunch of qualifier to funcation type has no meaning warnings. As well I get a condiation expression of type 'overloaded-function is illegal. I am using VS.Net 2003. Any ideas on what I am missing. As well can I get my cake and eat it to by making the CheckFunc virtual and have it resolve to the derived form? TIA Mark Loew, MCSD, MCSE Application Development Consultant Sagestone Consulting www.sagestone.com <http://www.sagestone.com/> Grand Rapids, MI 616-954-9556 x149 Microsoft Gold Certified Partner mloew(a)sagestone.com

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boost regex and match_partial
by Angus Leeming 26 Sep '03

26 Sep '03

I'm afraid I haven't got the hang of match_partial. Below is a little code with two functions that I think should produce identical results, but don't. In strip_commas_try1 I use: boost::regex const front("^( *[[],*)(.*)$"); regex_match(it, end, what, front); In strip_commas_try2 I use: boost::regex const front("^( *[[],*)"); regex_match(it, end, what, front, boost::match_partial); Why does this second case not result in what[0].matched ? Many thanks, Angus (This is with BOOST_VERSION 103002 and g++ (GCC) 3.2 20020903 (Red Hat Linux 8.0 3.2-7)). #include<iostream> #include<string> #include <boost/regex.hpp> using std::string; string const strip_commas_try1(string const & input) { string::const_iterator it = input.begin(); string::const_iterator end = input.end(); // Strip any commas that follow immediately after the '['. // "[,,,,foo..." -> "foo..." boost::regex const front("^( *[[],*)(.*)$"); boost::smatch what; regex_match(it, end, what, front); if (!what[0].matched) { std::cout << "Try 1 failed" << std::endl; return string(); } it = what[1].second; string const result = string(it, end); std::cout << "Try 1: " << result << std::endl; return result; } string const strip_commas_try2(string const & input) { string::const_iterator it = input.begin(); string::const_iterator end = input.end(); // Strip any commas that follow immediately after the '['. // "[,,,,foo..." -> "foo..." boost::regex const front("^( *[[],*)"); boost::smatch what; regex_match(it, end, what, front, boost::match_partial); if (!what[0].matched) { std::cout << "Try 2 failed" << '\n'; return string(); } it = what[1].second; string const result = string(it, end); std::cout << "Try 1: " << result << std::endl; return result; } int main() { string const input = "[,,,foo,,,,bar,,,gaz,,]"; std::cout << "Input: " << input << std::endl; strip_commas_try1(input); strip_commas_try2(input); return 0; }

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indirect_iterator_generator and std::distance ambiguity
by Jeff Flinn 24 Sep '03

24 Sep '03

I'm having problems compiling the code below with boost_1_30_2 and VC71 complaining about: ...\Microsoft Visual Studio .NET 2003\Vc7\include\xutility(489) : error C2665: 'std::_Distance2' : none of the 4 overloads can convert parameter 4 from type 'std::iterator_traits<_Iter>::iterator_category' with [ _Iter=CDictionary::tVarConstItr ] ... Replacing with std::distance( lBeg.base(), lItr.base() ) does compile and work properly. Am I missing something in the typedef of tVarConstItr that would allow direct usage? ---------------------------------------------------------- class CDictionary { ... class VarSpec { ... typedef boost::shared_ptr<VarSpec> tPtr; }; typedef VarSpec tVar; typedef tVar::tPtr tVarPtr; typedef std::vector<tVarPtr> tVars; typedef boost::indirect_iterator_generator < tVars::const_iterator , tVar , tVar& , tVar* , std::iterator_traits<tVars::const_iterator> ::iterator_category >::type tVarConstItr; typedef boost::indirect_iterator_generator < tVars::iterator , tVar , tVar& , tVar* , std::iterator_traits<tVars::iterator> ::iterator_category >::type tVarItr; tGroups Groups()const{ return mGroups; } tVarItr VarBegin() { return tVarItr ( mVars.begin() ); } tVarItr VarEnd () { return tVarItr ( mVars.end () ); } tVarConstItr VarBegin()const{ return tVarConstItr( mVars.begin() ); } tVarConstItr VarEnd ()const{ return tVarConstItr( mVars.end () ); } }; usage: ------ int CDictionaryEditorView::Idx( const TCHAR* aChrPtr, bool aExact )const { boost::function1<bool,const CDictionary::VarSpec&> lFindFnc; if( aExact ) { lFindFnc = boost::bind( std::equal_to<std::string>() , std::string(aChrPtr) , boost::bind( &CDictionary::VarSpec::Name, _1 ) ); } else { //... } CDictionary::tVarConstItr lBeg = mDctPtr->VarBegin(); CDictionary::tVarConstItr lEnd = mDctPtr->VarEnd (); CDictionary::tVarConstItr lItr = std::find_if( lBeg, lEnd, lFindFnc ); return (lItr!=lEnd)? std::distance( lBeg, lItr ) : -1; } -- Jeff Flinn Applied Dynamics, International

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[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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