October 2008 - Boost-users - lists.preview.boost.org

How can I use unique_ptr with container and string in boost::interprocess?
by blp330 21 Oct '08

21 Oct '08

Hi, I have a complex data structure that wants to put into shared memory. In STL way it should be: list<tuple<string, string, map<string, string>>> As you can see, there are a lot of strings which will be put into shared memory. My current way to a string into a container is (I use list<string> as a example): typedef allocator<char, managed_windows_shared_memory::segment_manager> CharAllocator; typedef basic_string<char, std::char_traits<char>, CharAllocator> SharedMemoryString; typedef allocator<SharedMemoryString, managed_windows_shared_memory::segment_manager> PushValueAllocator; typedef list<PushValue, PushValueAllocator> PushQueue; In this way, I always must construct a SharedMemoryString first then put it into container: SharedMemoryString mStr(charAlloc); mStr = "some stirng..."; queue->push_back(mStr); In my understanding, this will cost twice memory allocations to store this string into shared memory. First time is mStr = "some string...", second time is that mStr is put into list container, then mStr's memory will be destructed after leaving the scope. This means if the string length is 1KB, my shared memory size at least must be 2 * 1KB + container overhead. This seems stupid because twice memory allocation and copy operation. So, I want to use unique_ptr to solve this problem. I try: typedef managed_unique_ptr<SharedMemoryString, managed_windows_shared_memory>::type StringUniquePtr; typedef allocator<StringUniquePtr, managed_windows_shared_memory::segment_manager> PushValueAllocator; typedef list<PushValue, PushValueAllocator> PushQueue; SharedMemoryString* mStr = new SharedMemoryString(charAlloc); *mStr = "some stirng..."; queue->push_back(StringUniquePtr(make_managed_unique_ptr(mStr, segment))); But it can't compile... :( I have no idea to make unique_ptr to work with string in container in boost::interprocess. How do I make this work? Thank you very much. -- View this message in context: http://www.nabble.com/How-can-I-use-unique_ptr-with-container-and-string-in… Sent from the Boost - Users mailing list archive at Nabble.com.

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Re: [Boost-users] [graph] Newbie question: iterator shows vertices not added, always lo .. hi
by Cooprider, Nathan (US SSA) 21 Oct '08

21 Oct '08

Let me start off by saying I'm fairly new as well, but I won't let that stop me from putting my foot in my mouth: > Perhaps this behavior is dictated by my choices of data structures vecS? This would be my guess as well. Did you try using a different structure to see if the behavior changes? > Is the Boost book is (substantially?) better than using the online docs, > or is it just the same content on paper? I found the BGL book to be helpful to a certain degree. The walkthroughs and examples seem easier to follow, and the index and table of contents are helpful to have at one's fingertips. Unfortunately, it is a bit old and so some important features are not covered in the book at all (property bundles, subgraphs). For those you have to rely on the online documentation. Nathan

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Re: [Boost-users] Boost [Asio] Problem with POST Request and async_read
by anti00Zero 21 Oct '08

21 Oct '08

I Found the problem myself. The problem was transfer_at_least(1). I should write the hole content to the thhp server and after this I should read. With transfer_at_least(1) I wrote some content and want to read again from the server. But the server wants to recieve more content. >Hello. > >I've wrote a SSL Proxy and have a big problem. >I use a HTTP Client in bei Proxy to communicate with my HTTP Server. >HTTP Client and HTTP Server are localhost. A SSL Browser should call my local SSL Proxy and internal >a HTTP Client communicate with my HTTP Server. >If the SSL Brower sends a POST request to my proxy, I have a problem. > >This is my code: > >async_write(m_HTTPSocket, buffer(m_sSSLRequestBuffer), > transfer_at_least(1), > boost::bind(&CSession::HandleHTTPWriteRequest, this, placeholders::error)); > >void CSession::HandleHTTPWriteRequest(const error_code& error) >{ > if (!error) > { > async_read(m_HTTPSocket, buffer(m_HTTPResponse, >MAX_HTTPRESPONSE_BUFFER_LENGTH), > transfer_at_least(1), > boost::bind(&CSession::HandleHTTPReadResponse, this, placeholders::error, > placeholders::bytes_transferred)); > } > else if(error != error::eof) > { > SendErrorToSSL(error); > } >} > >void CSession::HandleHTTPReadResponse(const error_code& error, size_t iTransferredBytes) >{ > if(!error) > { > >The error is boost::asio::error::connection_aborted (10053 (WSAECONNABORTED)). If I don't use my >SSL Proxy the HTTP Browser works correct. > >I use Visual Studio 2005 with Boost 1.36 > >Thanks for help. -- GMX startet ShortView.de. Hier findest Du Leute mit Deinen Interessen! Jetzt dabei sein: http://www.shortview.de/wasistshortview.php?mc=sv_ext_mf@gmx

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error when using boost::thread_group
by Meng Yu 21 Oct '08

21 Oct '08

Dear all, I delted the boost folder carelessly,so I had to rebuild boost1_33_1. after i build bjam,I can compile ,run the thread.cpp in /boost_1_33_1/libs/thread/example/ but,when I compile and run the thread_group.cpp,I got these message: (gdb) bt #0 ~function0 (this=0xbffaacd0) at function_template.hpp:313 #1 0x080497c6 in main (argc=1, argv=0xbffaada4) at thread_group.cpp:17 (gdb) step Program received signal SIGSEGV, Segmentation fault. [Switching to Thread -1208067152 (LWP 29013)] 0x08049c57 in boost::detail::function::void_function_invoker0<void (*)(), void>::invoke (function_ptr= {obj_ptr = 0xb7fe53af, const_obj_ptr = 0xb7fe53af, func_ptr = 0xb7fe53af, data = "?}) at function_template.hpp:103 103 BOOST_FUNCTION_RETURN(f(BOOST_FUNCTION_ARGS)); and I got the same message when I use thread_group my system version :Linux version 2.6.9-5.EL ( bhcompile(a)decompose.build.redhat.com) (gcc version 3.4.3 20041212 (Red Hat 3.4.3-9.EL4)) boost:1.33.1

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[Proto] Extracting types of sub-expression in transform
by Ivan Godard 21 Oct '08

21 Oct '08

Eric Niebler wrote: Anybody who understands van Wijngaarden grammars can help by explaining them to me in small words. :-) A van Wijngaarden Grammar definition for some target language (Algol68 in this case) is essentially an executable program written in a text substitution language i.e. VWG itself. If a candidate program purportedly written in the language defined by the grammar (Algol68) is submitted to an interpreter for the VWG language definition and the result is the empty string then the submitted program is well formed according to the grammar. If the result of the exercise is not the empty string then the submitted program contains an error. The content of the left-over string (if one happens) is a clue about what was wrong in the submitted program, but practical compilers do not just run the submitted program against the grammar and tell you the result if any. Instead, the grammar is turned into a more conventional parser (automatically one hopes) so that actions can be performed as the grammar engine does the substitutions. These actions kick out the intermediate code for conventional middle- and back-ends. Note that such a parser is not pure syntax - because the VWG grammar embeds type and semantic constraints as well as syntactic ones, the actions can contain type and semantic behavior as well as conventional ASTs (Abstract Syntax Trees) - no separate bug-ridden semantic pass is needed. You can validly see the VWG definitional mechanism as merely writing a canonical compiler for the target language and then using that compiler for the definition. The advantage of writing this compiler in VWG instead of say C is the brevity and rigor of the grammar representation. However, VWG does not remove the fundamental ontological paradox involved in language definition and indeed involved in mathematics itself, where the problem of axioms remains since the Greeks. Ivan p.s. a tutorial for two-level Grammars is at http://homepages.cwi.nl/~steven/vw.html, but the surface syntax (of the Grammar) is somewhat different from that used in the Report. p.p.s. Also note that VWG is only a notational device for language definition; it still leaves the definition of the language itself up to the designer. Consequently designing a practical language remains. Thus it is trivial to write a VWG grammar that contains free non-terminals such that the syntax check of a candidate program in the defined language is equivalent to the halting problem. You thought gcc was slow? As a practical matter Algol68 was carefully defined to be LL(1) and compilable by a one-pass compiler with single-symbol lookahead, but that was the choice of the designers and not required by VWG. Would that C had been so designed! :-)

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[Boost.Python] Can't work out what an extractor does
by Kirit Sælensminde 21 Oct '08

21 Oct '08

I've been puzzling around about how to deal with converting my string type to/from Python. I've managed to get one part of the puzzle solved, but can't work out from the documentation what the other part is. The code I have so far is this: namespace { struct to_pystr { static PyObject *convert( const fostlib::string &s ) { std::wstring u( fostlib::coerce< std::wstring >( s ) ); return PyUnicode_FromWideChar( u.c_str(), u.length() ); } static PyTypeObject const* get_pytype() { return &PyUnicode_Type; } }; } BOOST_PYTHON_MODULE( crypto ) { using namespace boost::python; // fostlib::string fostlib::sha1( const fostlib::string& ) def( "sha1", fostlib::sha1 ); implicitly_convertible< fostlib::native_string, fostlib::string >(); to_python_converter< fostlib::string, to_pystr, false >(); } This works ok if the Python type is str, but it doesn't work for unicode strings: Boost.Python.ArgumentError: Python argument types in crypto.sha1(unicode) did not match C++ signature: sha1(fostlib::string) What I guess I need is some way to wrap the Python call PyUnicode_FromObject in order to construct my string type, probably from PyObject, but certainly from unicode. From the documentation at [1] it isn't at all clear what actually needs to be done -- I can't even tell from that what the function signature I need to code to is. I think this [2] is relevant, but can't work out in what way -- no mention is made of where the reference object comes from and nor is there an example of the implementation of a simple extractor concept -- the internal implementations of the ones given on the page are far from illuminating. [1]http://www.boost.org/doc/libs/1_36_0/libs/python/doc/v2/Extractor.html [2]http://www.boost.org/doc/libs/1_36_0/libs/python/doc/v2/lvalue_from_pytyp… It looks like there's some good emails linked from this page [3], but unfortunately the links to the Python list archives are broken. [3]http://www.boost.org/doc/libs/1_36_0/libs/python/doc/internals.html I did think about exposing my string class, but the __unicode__ operator doesn't seem to be supported. Adding it to the relevant Boost.Python headers doesn't appear to be enough to get it working and I don't think that is the right way to do this either. So, basically, I guess there ought to be a fairly simple way to add this sort of type conversion into the Boost.Python type registry, but it appears to be undocumented and I can't see anything for this in the examples or the tests in the library either. K

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end of line continuation for parse_config_file function
by Muktipada Behera 21 Oct '08

21 Oct '08

namespace po = boost::program_options does parse_config_file function support an end-of-line continuation using the backslash character '\' in INI file. One should be able to specify libraries as follows: ink_library = tc300c10v10v_hs_levelshifter_worst.db_Tj125_pg \ tc300c10v12v_hs_levelshifter_worst.db_Tj125_pg \ tc300c10v_hs_worst.db_Tj125_pg:tc300c10v_lp_worst.db_Tj125_pg Similarly, always_on_signals as: always_on_signals = tb.u_top.uSD_BLK.tmp31,\ tb.u_top.uSD_BLK.tmp32, \ tb.u_top.uSD_BLK.out3 Besides readability, we may run into issues due to number of characters per line allowed without support for backslash. Any help will be appreaciated. Regards, -mukti __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Segmentation fault when using std::string in stl::maps in shared memory
by hamsinv 21 Oct '08

21 Oct '08

Hello All, I have been trying boost library for sharing stl::maps using shared memory. I am able to run the example code on sharing stl::maps successfully. It uses int-float pair to store in map. I have to store std::string-int pair. Writing into the map, works fine, yet reading the same from a different process results in Segmentation fault. Both the Process are as follows: Process1.cpp --------------------- ////////////////////////////////////////////////////////////////////////////// // // (C) Copyright Ion Gaztanaga 2006-2007. Distributed under the Boost // Software License, Version 1.0. (See accompanying file // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // // See http://www.boost.org/libs/interprocess for documentation. // ////////////////////////////////////////////////////////////////////////////// #include <iostream.h> #include "boost/interprocess/detail/config_begin.hpp" #include "boost/interprocess/detail/workaround.hpp" //[doc_map #include "boost/interprocess/managed_shared_memory.hpp" #include "boost/interprocess/containers/map.hpp" #include "boost/interprocess/allocators/allocator.hpp" #include <functional> #include <utility> int main () { using namespace boost::interprocess; shared_memory_object::remove("MySharedMemory"); try{ managed_shared_memory segment (create_only ,"MySharedMemory" //segment name ,65536); //segment size in bytes typedef int KeyType; typedef std::string MappedType; typedef std::pair<const int, std::string> ValueType; typedef allocator<ValueType, managed_shared_memory::segment_manager> ShmemAllocator; typedef map<KeyType, MappedType, std::less<KeyType>, ShmemAllocator> MyMap; ShmemAllocator alloc_inst (segment.get_segment_manager()); MyMap *mymap = segment.construct<MyMap>("MyMap") //object name (std::less<int>() //first ctor parameter ,alloc_inst); //second ctor parameter //Insert data in the map for(int i = 0; i < 10; ++i){ cout<<"I value is: "<<i<<endl; mymap->insert(std::pair<const int,std::string>(i,"Hello")); } mymap = segment.find<MyMap>("MyMap").first; cout<<"Shared memory map created"<< mymap<<endl; for( MyMap::iterator it = mymap->begin();it != mymap->end();++it) { cout<<"key: "<<(*it).first<<" Value: "<<(*it).second<<endl; } } catch(...){ shared_memory_object::remove("MySharedMemory"); throw; } return 0; } Process2.cpp -------------------- ////////////////////////////////////////////////////////////////////////////// // // (C) Copyright Ion Gaztanaga 2006-2007. Distributed under the Boost // Software License, Version 1.0. (See accompanying file // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // // See http://www.boost.org/libs/interprocess for documentation. // ////////////////////////////////////////////////////////////////////////////// #include <iostream.h> #include "boost/interprocess/detail/config_begin.hpp" #include "boost/interprocess/detail/workaround.hpp" //[doc_map #include "boost/interprocess/managed_shared_memory.hpp" #include "boost/interprocess/containers/map.hpp" #include "boost/interprocess/allocators/allocator.hpp" #include <functional> #include <utility> int main () { using namespace boost::interprocess; try{ managed_shared_memory segment (open_only ,"MySharedMemory" //segment name ); typedef int KeyType; typedef std::string MappedType; typedef std::pair<const int, std::string> ValueType; typedef allocator<ValueType, managed_shared_memory::segment_manager> ShmemAllocator; typedef map<KeyType, MappedType, std::less<KeyType>, ShmemAllocator> MyMap; MyMap *mymap = segment.find<MyMap>("MyMap").first; //object name for( MyMap::iterator it = mymap->begin();it != mymap->end();++it) { cout<<"key: "<<(*it).first<<" Value: "<<(*it).second<<endl; } } catch(...){ shared_memory_object::remove("MySharedMemory"); throw; } return 0; } Could anyone please tell me what's going wrong and how can i use std::string as key and int as value. Thank you. -- View this message in context: http://www.nabble.com/Segmentation-fault-when-using-std%3A%3Astring-in-stl%… Sent from the Boost - Users mailing list archive at Nabble.com.

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How does BOOST_TYPEOF works?
by Peng Yu 21 Oct '08

21 Oct '08

Hi, I tried to read the source code to figure out how BOOST_TYPEOF works. But I still don't understand how it works. Can somebody tell me how it works? Thanks, Peng

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Multi-Array indexing
by todd keeler 20 Oct '08

20 Oct '08

Hi, I'd like to understand how the Boost Multi-array implements multiple indexing using the regular square bracket operator. I've waded through the template code for a few hours, from what I understand, there's a nested bunch of sub-arrays which leads to a final object which offers a reference into the data array. I still can't figure out, however, how it solves this problem: Consider a Multi-Array A with dimension 3, Calling A[ i ][ j ][ k ] requires a call to A[ i ] which returns a Subarray, S1 The subarray gets indexed S1[ j ] and another subarray S2 is returned. however S2[k] doesn't return a subarray, but a reference to the data in the multiarray. However, S1 and S2 are the same object (subarray), hence require the same overloaded operator, returning the same type. making this unfeasible. Therefore, the only way I can think to eliminate this dilemma is to have a different object type for every dimension. I'm not sure if this is what Multi-array does, but I'd sure like to know how it's done . Thanks Todd

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