April 2007 - Boost-users - lists.preview.boost.org

[serialization] Suggestion for documenting stream_error
by Oleg V. Zhylin 06 Apr '07

06 Apr '07

Hi, I have an experience of debugging stream_error problem. It appeared that I was saving pointer and loading reference. I suggest such a mistake is common enough to be documented at http://www.boost.org/libs/serialization/doc/exceptions.html#stream_error WBR Oleg V. Zhylin ovz(a)yahoo.com ____________________________________________________________________________________ Never miss an email again! Yahoo! Toolbar alerts you the instant new Mail arrives. http://tools.search.yahoo.com/toolbar/features/mail/

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why STLport?
by n.torrey.pines＠gmail.com 06 Apr '07

06 Apr '07

I'm curious, are there reasons to use STLport with GCC + Boost instead of GCC's own library? Better debugging?

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[1.34] using STLport 5.1.0 fails during linking
by Vincent Torri 05 Apr '07

05 Apr '07

Hello, I'm trying to build Boost 1.34 using STLport 5.1(.0), but I get those error messages during link: /usr/bin/ld: cannot find -lstlportstlg.5.1 /usr/bin/ld: cannot find -lstlport.5.1 I use Linux and gcc 4.1.2. The static libs of STLport exist, but without the version number. Here is how I compile and install STLport: tar jxvf STLport-5.1.0.tar.bz2 cd STLport-5.1.0/build/lib make -f gcc.mak depend make -f gcc.mak make -f gcc.mak all-static make -f gcc.mak install make -f gcc.mak install-static cd ../.. cp lib/libstlport* $HOME/local/lib/ cp -R stlport $HOME/local/include/ Here are the available static libs: libstlport.a libstlportg.a libstlportstlg.a Note: I've just compiled STLport 5.1.3. Same files. They didn't change the build system. Note bis: I've asked the STLport devs if I should link my project with static or shared lib of STLport. They answered the shared lib as it is less troublesome. Maybe Boost should also do that. I modified user-config.jam by adding ($HOME == /home/torri): using stlport : 5.1.0 : "/home/torri/local/stlport" "/home/torri/local/lib" ; I compiled Boost with that command line: ../../boost-jam-3.1.13-1-linuxx86/bjam --prefix=$HOME/local stdlib=stlport --toolset=gcc If needed, I can provide more informations on my system. Vincent Torri

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Serialization problem with DLLs
by Gheury Edmond (DBB) 05 Apr '07

05 Apr '07

Hello, I am experiencing some trouble with the boost.serialization library. I'm using Visual Studio .Net 2003. My serialization code is located inside a specific DLL (i'm using polymorphic archives). When I want to save the data, there is no problem. But when I want to load previously saved data, it throws an "unregistered class" exception. Thus, I tried the following test: instead of building a DLL, I built the serialization code into a static ".lib" and relinked my program. Then everything worked fine. I tried to track down what threw the exception in the DLL code. I think the bug consequences show up in extended_type_info.cpp. The ktmap class is used to register the type keys. When the ktmap::insert is called the first time, it assigns the address of the static data "instance" to the m_self class attribute (like singletons). Then, after ktmap::insert has been called several times, the process enters serialization's load code and, when ktmap::find is called the first time, it does a check on m_self, which is NULL. Therefore, it exits without returning anything, causing a throw in the calling function (basic_iarchive). When I built the code into a static lib, the ktmap::insert calls occur like with the DLL code, but when ktmap::find is called, the "m_self" attribute hasn't been reset to NULL, and the data is loaded successfully. I don't know what to do, no warnings are issued when I compile the serialization DLL so I guess everything is OK on that side. Both the DLL and the lib are compiled using "multithreaded debug DLL" option in the code generation tab, which works fine for everything else. I did some googling and didn't find any thread mentionning that specific problem. Has anyone suggestions to solve this problem ? Thank you very much, Edmond. -------------------------------------- Dexia Bank disclaimer : http://www.dexia.be/maildisclaimer.htm --------------------------------------

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Boost Con question
by Elisha Berns 05 Apr '07

05 Apr '07

Boost Conference Organizers, The conference schedule and program looks great. There is just one thing I would like to know: can participants receive/access something on the order of recordings and slides of the sessions? That way I don't need to fret about missing a session or track I can't physically attend. Thanks for the clarification, Elisha Berns

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[RFC] Preferred API for a CGI library proposal
by Darren Garvey 05 Apr '07

05 Apr '07

Hello all, This may seem off-topic, but I assure you it isn't. ;) This is an initial probe for ideas about an API for [any] upcoming CGI library submission. I have my own ideas, but I don't think putting them here would be particularly relevant. The reason I'm asking such an open-ended question is that I'm assuming lots of people here will have experience using CGI libraries (possibly in other languages, possibly your own) and may have specific ideas about what should or shouldn't move from them into a Boost.CGI library, if one were accepted. Whether or not you see the point of a C++ CGI library, your comments on APIs provided by other languages would still be very much appreciated! Cheers, Darren

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[pool] Does alloc_size waste memory?
by Soren Soe 05 Apr '07

05 Apr '07

Hi, I am trying to replace an old implementation of a small object memory allocator with boost::pool. I have noticed that boost::pool uses quite a bit more memory for certain requested_size than the allocator I am trying to replace. After looking at the code and reading the Guaranteeing Alignment <http://www.boost.org/libs/pool/doc/implementation/alignment.html> document, I am wondering why boost::pool::alloc_size() have to be lcm(sizeof(void*), sizeof(size_type), requested_size)? Lots of bytes can be wasted in the chunks returned to user when requested_size is not a multiple of min_alloc_size (lcm(sizeof(void*), sizeof(size_type))). I would think the requested_size alignment could be the first multiple of min_alloc_size that is larger than requested_size. For example, the convoluted example in the alignment document has requested_size==7, sizeof(void*)==3, and sizeof(size_type)==5. Currently alloc_size() returns lcm(3,5,7)==105, but since min_alloc_size is lcm(3,5)==15, I think requested_size alignment could be 15 bytes, rather than the 105 bytes. Another way to look at this. If requested_size was changed to 15, then the current implementation of alloc_size() would return 15 bytes (lcm(3,5,15)==15), so why the huge penalty when requested size is 7? Am I missing something? Thank you. Soren

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boost::filesystem and an odd linker error.
by Matt Handley 05 Apr '07

05 Apr '07

Hi. I'm having difficulty using the boost::filesystem library. I have checked-out the source from the CVS repository, and ran: /usr/local/bin/bjam --v2 --toolset=darwin --with-regex --with- serialization --with-filesystem --layout=system --prefix=SOMEDIR variant=release threading=single link=shared install Thinking that it would install headers in SOMEDIR/include and SOMEDIR/ lib. That it did. However, when I try to compile the simple_ls.cpp example, I get the following errors: $ g++ -o simple_ls simple_ls.cpp -Llibraries/lib -lboost_filesystem - lboost_system /usr/bin/ld: Undefined symbols: boost::filesystem::initial_path() boost::filesystem::is_directory(boost::filesystem::path const&) boost::filesystem::system_complete(boost::filesystem::path const&) boost::filesystem::path::path(char const*, bool (*) (std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)) boost::filesystem::detail::dir_itr_init (boost::shared_ptr<boost::filesystem::detail::dir_itr_imp>&, boost::filesystem::path const&) boost::filesystem::detail::dir_itr_increment (boost::shared_ptr<boost::filesystem::detail::dir_itr_imp>&) boost::filesystem::detail::dir_itr_dereference (boost::shared_ptr<boost::filesystem::detail::dir_itr_imp> const&) boost::filesystem::exists(boost::filesystem::path const&) boost::filesystem::path::native_file_string() const boost::filesystem::path::native_directory_string() const boost::filesystem::path::leaf() const collect2: ld returned 1 exit status Which is a bit odd. The contents of the libraries/lib directory: $ ls libraries/lib/libboost* libraries/lib/libboost_filesystem.dylib libraries/lib/ libboost_serialization.dylib libraries/lib/ libboost_wserialization.dylib libraries/lib/libboost_regex.dylib libraries/lib/ libboost_system.dylib Why is this simple program not linking? Matt

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[guid] Linker Error when using precompiled headers
by Christian Henning 05 Apr '07

05 Apr '07

Hi there, there is a problem with the free flowing functions random_byte(...) and swap(...). stdafx.obj : error LNK2005: "unsigned char __cdecl boost::detail::random_byte(void)" (?random_byte@detail@boost@@YAEXZ) already defined in database.obj stdafx.obj : error LNK2005: "void __cdecl boost::swap(class boost::guid &,class boost::guid &)" (?swap@boost@@YAXAAVguid@1@0@Z) already defined in database.obj To solve that one would need to move the functions inside a structure. For example: namespace boost { namespace detail { struct utilities { static uint8_t random_byte() { ... } }; }} Christian

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[FileSystem] can't use path class
by Alexander Fradiani 05 Apr '07

05 Apr '07

Hello. I can't initialize the path class with a char* argument. I'm using cygwin, with the boost libraries installed as part of the cygwin installation packages. this is the code: #include "boost/filesystem/operations.hpp" #include "boost/filesystem/path.hpp" #include <iostream> #include <string> using namespace boost::filesystem; using namespace std; int main() { path mypath("/code/fileMan.txt"); return 0; } and the error i get when trying to compile with g++ is: "undefined reference to boost::filesystem::path::path(char const*)" I dont know exactly what is wrong, this is the first time i use the boost libraries so i really appreciate some help, thanks _________________________________________________________________ Charla con tus amigos en línea mediante MSN Messenger: http://messenger.latam.msn.com/

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