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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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