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bug in boost::random?
by boost＠larroy.com 24 Sep '06

24 Sep '06

Hi, First of all boost::random is very clever and complete, thanks! Using boost::random I found uniform_int distribution not working in my box. I have version 1.33 on a Debian system. This is an example of a program that triggers a non-uniform integer distribution. I'm I doing something wrong? Regards. #include <iostream> #include <string> #include <cstdlib> #include <cassert> #include<vector> #include<stdexcept> #include <boost/random.hpp> #include <limits> using namespace std; int main(int argc, char *argv[]) { boost::mt19937 rng; boost::uniform_int<int64_t> ui(numeric_limits<int64_t>::min(),numeric_limits<int64_t>::max()); boost::variate_generator<boost::mt19937&, boost::uniform_int<int64_t> > rgen(rng, ui); while(true) { cout << rgen() << endl; } } -- Pedro Larroy Tovar, pedro at larroy dot com | http://pedro.larroy.com/ * Las patentes de programación son nocivas para la innovación * http://proinnova.hispalinux.es/

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VS2003 Linking issuse
by Anthony Mason 22 Sep '06

22 Sep '06

Hi guys, I know this is probably a common problem, but I haven't found any help on any google searches so far... I've got my app compiling in debug mode fine using the boost_date_time and boost_filesystem libraries, compiling using Multithreaded Debug, but when I set up my Release mode compile using just plain Multithreaded I get a ton of LNK2005 messages similar to : error LNK2005: "public: static unsigned int const std::ctype<char>::table_size"(?table_size@$ctype@D@std@@2IB)already defined in libboost_date)time-vc71-mt-s-1_33_1.lib(greg_month.obj) I get about 70 of these errors between date_time and filesystem libraries. I'm linking against the same libraries (mt-s) both debug and release mode. I was hoping that someone could give me some advice. Thanks, Anthony

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[iostreams] Implementing a block cipher as a filter
by Pfligersdorffer, Christian 22 Sep '06

22 Sep '06

Dear community, I'm on my way to learn writing filters for the iostreams library and find it very hard. I want to compress and encrypt data, so I use the gzip-filters (that are already provided) and some self-tailored crypto-filter. Using a symmetric block cipher should be just fine with the framework, since data from a stream is usually fed in portions to the filter (128 Bytes by default). Of course not when you use an aggregate_filter, which was my first attempt because it is so simple. Implementing a multichar_dual_use_filter seemed simple too but I am experiencing weird behaviour. Such as having runtime errors when reading an encrypted compressed file but not when reading compressed encrypted files. Also I am not entirely sure that I understood the documentation... Here is what I do, perhaps you gurus instantly see what I'm doing wrong: _________________________________________________________________________ class block_crypter : public boost::iostreams::multichar_dual_use_filter { const std::string pw; char* buffer; int length; void reallocate_buffer(std::size_t n) { if (length < n) { if (buffer) free(buffer); buffer = (char*) malloc(n); length = n; } } public: block_crypter(const char* password) : pw(password), buffer(NULL), length(0) {} ~block_crypter() { if (buffer) free(buffer); } template<typename Source> std::streamsize read(Source& src, char* s, std::streamsize n) { // Read up to n filtered characters into the buffer s, // returning the number of characters read or -1 for EOF. // Use src to access the unfiltered character sequence reallocate_buffer(n); std::streamsize count = boost::iostreams::read(src, buffer, n); assert(count <= n); if (count <= 0) return -1; decrypt(pw, buffer, count, s); return count; } template<typename Sink> std::streamsize write(Sink& dest, const char* s, std::streamsize n) { // Consume up to n filtered characters from the buffer s, // writing filtered characters to dest. Return the number // of characters consumed. reallocate_buffer(n); encrypt(pw, s, n, buffer); std::streamsize count = boost::iostreams::write(dest, buffer, n); assert(count <= n); return count; } }; BOOST_IOSTREAMS_PIPABLE(block_crypter, 0) _________________________________________________________________________ The encrypt() and decrypt() functions produce a character sequence of the exact same length as the input sequence. All char values can occur which might be a problem but I don't know. Runtime errors always occur at the end of the stream, i.e. on the last run of the filter. Perhaps I did not understand the EOF mechanics or am mixing up something. But then, it compiles and seems to behave properly if used alone. Only in read-mode preceding gzip-deflation there is an error. I hope someone can help me there. BTW: I did not even try to implement my filter as symmetric_filter. I cannot see how anyone would be able to do this given the present documentation or existing "examples". Another thing that clearly arises is the block size issue n which has to be the same for writing and reading in order to produce the correct plain text again. Maybe the optimally_buffered_tag should be used instead of trusting in always the same default filter buffer size? Thanks for your suggestions, -- Christian Pfligersdorffer Dipl.-Ing. Bakk.rer.nat. Software Engineering EOS GmbH - Electro Optical Systems Robert-Stirling-Ring 1 D-82152 Krailling / Munich Phone +49 89 893 36-229 Fax +49 89 893 36-287 christian.pfligersdorffer(a)eos.info http://www.eos.info

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boost::interprocess::managed_external_buffer class restrictions
by alexmark 22 Sep '06

22 Sep '06

The problem is the class managed_external_buffer currently does not provide public default c-tor and interface functions create(), open(), close(). I'm writing DLL, where I need a global object of type managed_external_buffer. This object is "connected" to mapped view of paging file within processing of DLL_PROCESS_ATTACH and disconnected at DLL_PROCESS_DETACH like that: HANDLE g_hfm; LPVOID g_buf_base_addr; managed_external_buffer g_buf; BOOL APIENTRY DllMain(,,,. ULONG reason, ...) { switch (reason) { case DLL_PROCESS_ATTACH: if (!Attach()) return FALSE; break; case DLL_PROCESS_DETACH: Detach(); break; } return TRUE; } bool Attach () { ... g_hfm = CreateFileMapping(0xFFFFFFFF, ...); // use paging file g_buf_base_addr = MapViewOfFile(g_hfm, ...); g_buf.create(g_buf_base_addr, ...); ... MyObj* p = g_buf.construct(...); ... } void Detach () { ... g_buf.destroy_ptr(p); ... g_buf.close(); UnmapViewOfFile(g_buf_base_addr); CloseHandle(g_hfm); ... } As a workaround, I wrote my own class "managed_user_buffer" derived from boost::interprocess::detail::basic_managed_memory_impl and providing public default c-tor and create()/open()/close() methods. I just made a copy of managed_external_buffer.hpp and slightly modified the code. But it's not so clear, why managed_external_buffer class itself exposes the restricted interface? I suppose the class would be more usable w/o the restrictions like that. Or not? Moreover, in boost::shmem::named_shared_object class this functionality was available. Thanks, Alex.

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BGL and maximum spanning trees
by aitor 22 Sep '06

22 Sep '06

Hello, in my project i need to compute the maximum spanning tree of an undirected weighted graph. One possible solution is to could iteratively convert each weight wij to 1/wij and apply prim_minimum_spanning_tree algorithm over it. However, i wonder if i could slightly change the prim_minimum_spanning_tree algorithm to a prim_maximum_spanning_tree function by changing only the compare predicate (in line 39 of prim_minimum_spanning_tree.hpp) from std::less<W> compare; to std::greater<W> compare; Wold then the function compute a maximum spanning tree ? Or am i missing something important ?

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boost+stlport+Xcode
by Don Agro 22 Sep '06

22 Sep '06

Has anyone had any luck linking boost into an XCode application that is also using STLport ? I am using STLport 5.0.0 and boost 1.33.1 Boost links in fine unless I also link in STLport then I have one undefined symbol... boost::signals::detail::signal_base::signal_base (boost::function2<bool, boost::signals::detail::stored_group, boost::signals::detail::stored_group, stlp_std::allocator<boost::function_base> > const&, boost::any const&) bjam build (with STLport at "/STLport-5.0.0" bjam -sSTLPORT_PATH="/" -sSTLPORT_VERSION="5.0.0" -sTOOLS="darwin" Any ideas ? Thanks in advance.

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[boost::filesystem] path namecheck : want to use "native" on Windows ?
by Washburn 22 Sep '06

22 Sep '06

I'm using Boost on Windows and the filesystem::path behaviour seems incorrect with the default name check, so I want to use the "native" namecheck instead. First of all, is this normal ? (since Boost is compiled for windows platformn should'nt the right name check be set by default ?) I initialize it manually using : filesystem::path::default_name_check( filesystem::native ) But since it can only be done once, this throws exceptions occasionnaly (not very important, but "ugly") Is there a better way to set the name check at the start of the application ? Washburn

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boost/pool/detail/mutex.hpp and threads on HP-UX
by mojmir.svoboda＠logicacmg.com 22 Sep '06

22 Sep '06

hello, i'm trying to build opendiameter (uses boost) with gcc 3.4.3 on a hp box: HP-UX bruno B.11.23 U 9000/800 1532750548 unlimited-user license and i've encountered following error when compiling libdiamparser: boost_1_33_1/boost/pool/detail/mutex.hpp:41:4: #error Unable to determine platform mutex type; define BOOST_NO_MT to assume single-threaded well, according to <sys/unistd.h> _POSIX_THREADS is still undefined on HP-UX: /************************************************************************ * The following defines are specified in the standard, but are not yet * implemented: * _POSIX_THREADS can't be defined until all features are implemented ... i've found similar problem in python and the solution uses check for _SC_THREADS instead of _POSIX_THREADS. yet better solution may use BOOST_HAS_PTHREADS: boost_1_33_1/boost/pool/detail $ diff -Naur mutex.hpp.orig mutex.hpp --- mutex.hpp.orig 2006-09-19 14:20:53.000000000 +0200 +++ mutex.hpp 2006-09-19 16:11:50.000000000 +0200 @@ -31,7 +31,7 @@ #define BOOST_MUTEX_HELPER BOOST_MUTEX_HELPER_WIN32 #else #include <unistd.h> - #ifdef _POSIX_THREADS + #ifdef BOOST_HAS_PTHREADS #define BOOST_MUTEX_HELPER BOOST_MUTEX_HELPER_PTHREAD #endif #endif @@ -45,7 +45,7 @@ # ifdef BOOST_WINDOWS # include <windows.h> # endif -# ifdef _POSIX_THREADS +# ifdef BOOST_HAS_PTHREADS # include <pthread.h> # endif #endif @@ -83,7 +83,7 @@ #endif // defined(BOOST_WINDOWS) -#ifdef _POSIX_THREADS +#ifdef BOOST_HAS_PTHREADS class pthread_mutex { @@ -107,7 +107,7 @@ { pthread_mutex_unlock(&mtx); } }; -#endif // defined(_POSIX_THREADS) +#endif // defined(BOOST_HAS_PTHREADS) #endif // !defined(BOOST_NO_MT) because the file <boost/config/platform/hpux.hpp> defines BOOST_HAS_PTHREADS for us on the hpux+gcc. is it allright? thanks fya, mojmir This e-mail and any attachment is for authorised use by the intended recipient(s) only. It may contain proprietary material, confidential information and/or be subject to legal privilege. It should not be copied, disclosed to, retained or used by, any other party. If you are not an intended recipient then please promptly delete this e-mail and any attachment and all copies and inform the sender. Thank you.

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boost::interprocess::managed_external_buffer - link errors
by alexmark 22 Sep '06

22 Sep '06

When I include boost/interprocess/managed_external_buffer.hpp in more than one file within a solution (MSVC 7.1) I get linker errors LNK2005 and LNK4006 because of boost::interprocess::fill_system_message(...) function redefinition. The same is applicable to the case when this header file is included in stdafx.h only. fill_system_message(...) is a standalone function, not a member of a class. And the body of it is included in header file. May it be the point the problem originates from? Maybe the better way is to move "fill_system_message(...)" to .cpp source file? Have anybody faced this problem? Thanks, Alex.

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How to do code factoring when using Boost.Program_options?
by Peng Yu 21 Sep '06

21 Sep '06

Hi, Suppose that I have program option set U. I have many programs which uses a subset of U as their options. Some of them share the same subset. For now, I code all the options in the main function like the one in the tutorial http://www.boost.org/doc/html/program_options/tutorial.html However, there is a problem when I have a lot programs with similar options. I would like to factor out the common code. But I don't have an idea how to do it in a good way. If you happen to have some experience, please let me know and share your experience with me. Thanks, Peng

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