December 2009 - Boost-users

boost port for S60 (Symbian)
by Yuriy Krasnoschek 12 Dec '09

12 Dec '09

Hello. I spent some efforts to make several libraries from boost compile and run on Symbian Series 60 with winscw (Code warrior by Nokia). I can share my work with community and continue porting, just need to know where to start. The problem is I was forced to modify original boost sources (like select_platform.hpp) and libraries files due to compiler / platfom limitations. Libraries that ran on S60 3rd Edition Feature Pack 2 + are: thread, date_time, system, regex, asio (partially) and of cource libraries that don't depend on platfom so much smart_pointers / type_traits / integer / etc. -- Best regards, Yuriy A. Krasnoschek aka D.Rider

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Getting metadata of class
by Alex Vinokur 12 Dec '09

12 Dec '09

Hi, Does Boost contain any features to get metadata of classes? For instance, Let Foo be some class class Foo { int m_var1; long* m_var2] char m_var3[100]; dooble m_var4; }; I would like to get the following info (as vector, file, etc) of its members: {" m_var1", "int", sizeof (m_var1), offset of (m_var1) }, {" m_var2", "long", "Pointer", sizeof (m_var2), sizeof (base-variable, i.e., long), offset of (m_var2 }, {" m_var3, "char", "array", sizeof (m_var3), sizeof (base-variable, i.e., char), offset of (m_var3 }, {" m_var4", "double", sizeof (m_var4), offset of (m_var4) }, That info I would like to get as a result of some feature (function, ...) applied to class Foo, not to each member of Foo. Alex.

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Re: [Boost-users] default mpi implementation
by Vladimir Prus 12 Dec '09

12 Dec '09

Sean Farrow wrote: > Hi: > > Could someone give me a url for the default mpi compiler used with > boost.mpi, I believe this is mpi++ but could be wrong. There's no default compiler -- a few will be probed. Specifically, this is what is probed on Unix: binaries named * mpic++ * mpiCC (supposedly used by MPICH) * mpicxx (supposedly used by OpenMPI and MPICH2) Does this help? - Volodya

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My First Boost Program At Work With Visual Studio
by Dave Schwartz 12 Dec '09

12 Dec '09

Hello Gurus, First, my 2 lines of appreciation to the community. I am new to boost library and I must tell, I have been enjoying myself going through various boost libraries and running sample programs provided. Must say all this has been quite straightforward and given me a headstart and confidence in learning the libraries. I have been trying the samples on my home PC with Visual Studio 2008 with the libraries provided by boostpro 1.4 installation. No issues. Yesterday I tried using the serialization library at work and wanted to serialize a simple class to an XML file and de-serialize it. This example worked on my home PC (visual studio 2008). On my work PC that has visual studio 2005, the compilation went fine but the program ended up generating a library as in InventoryConfig.lib, instead of the regular InventoryConfig.exe. Apparently it looks like the output type of the program changed from .exe to .lib on visual studio 2005 on my work computer. When I remove the serialization code, the output type goes back to .exe I copied the same code back to my home pc and with visual studio 2008 I get the correct result and the output type remains an executable as set initially while creating the project. Can't seem to figure out what project properties are getting changed on VS2005 when I use the library. I am not sure where to look or how to go about fixing this issue. Appreciate your help. Thanks a lot Dece

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condition_variable
by Alessandro Bellina 11 Dec '09

11 Dec '09

Hello, I am using boost condition_variables to block while waiting for an asynchronous response. I am seeing an error that happens at random whenever I am releasing the lock just before calling notify_one. The error goes away if I keep the lock and release after notify_one. Here is the code: class BlockingRequest{ public: // predicate class class ResponseStatus { public: ResponseStatus( bool& received ) : m_received( received ) { } bool operator()() const { return m_received; } private: bool& m_received; }; //blocking request std::string Request( const std::string& request ) { boost::mutex::scoped_lock lock( mutex ); //perform asynchronous request through network or something else, pass RequestHandler as a handler boost::posix_time::milliseconds timeoutDuration( 10000 ); //wait for 10 seconds if( !condition.timed_wait( lock, timeoutDuration, ResponseStatus( received ) ) ) { throw std::exception( "Request timed out" ); } return receivedMessage; } //some other thread calls this function void RequestHandler( const std::string& message, void* caller ) { BlockingRequest* myRequest = reinterpret_cast< BlockingRequest* >( caller ); boost::mutex::scoped_lock lock( myRequest->mutex ); myRequest->receivedMessage = message; myRequest->received = true; /* if this next line in bold is commented out, code works fine... contrary to Boost documentation. http://www.boost.org/doc/libs/1_41_0/doc/html/thread/synchronization.html#t… */ *lock.unlock();* myRequest->condition.notify_one(); } };

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privately inherit enable_shared_from_this?
by Eric J. Holtman 11 Dec '09

11 Dec '09

I have some code that uses enable_shared_from_this. I was publicly deriving, i.e. (and this works) class Request : public boost::enable_shared_from_this<Request> { }; I wanted to change my code around so that I wrapped the shared_from_this function inside the class, so that I could check at runtime whether certain conditions hold, i.e. class Request : private boost::enable_shared_from_this<Request> { public: boost::shared_ptr<Request> get_ptr () { if (conditions_are_good) return shared_from this (); else throw std::logic_error ("Bad get"); }; }; This won't compile (visual studio 2008). 1>Compiling... 1>Request.cpp 1>c:\boost\boost_1_40_0\boost\smart_ptr\enable_shared_from_this.hpp(50) : error C2243: 'type cast' : conversion from 'Request *' to 'boost::enable_shared_from_this<T> *const ' exists, but is inaccessible 1> with 1> [ 1> T=Request 1> ] 1> c:\boost\boost_1_40_0\boost\smart_ptr\enable_shared_from_this.hpp(48) : while compiling class template member function 'boost::shared_ptr<T> boost::enable_shared_from_this<T>::shared_from_this(void)' 1> with 1> [ 1> T=Request 1> ] 1> c:\src\cpp\trunk\request_lib\request.h(48) : see reference to class template instantiation 'boost::enable_shared_from_this<T>' being compiled 1> with 1> [ 1> T=Request 1> ] Can I get this to work?

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[integer]/cstdint.hpp How to use portable literals?
by vicente.botet 11 Dec '09

11 Dec '09

Hi, I need to use boost::intmax_t literals in a portable way. I remember some discussion related to this subject, but I've not found the thread. Could someone point me to these threads, or tell me how I can achieve this. I'm currently using the macro INTMAX_C, but it seems that this macro is not always defined. Thanks, _____________________ Vicente Juan Botet Escribá

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Recognition simple variables, pointers and arrays
by Alex Vinokur 11 Dec '09

11 Dec '09

Hi, Is there any Boost method/class that enables to recognize simple variables, pointers, arrays in C++? Something like: http://groups.google.com/group/alt.sources/browse_thread/thread/8b059c1df87… Alex

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[chrono] New Features + Bug fixes + Updated documentation
by vicente.botet 11 Dec '09

11 Dec '09

Hi, I'm pleased to annonce the new version of the Boost.Chrono library. Even if the library is not yet ready for review I wanted to share it with you. The library can be downloaded from the vault http://www.boostpro.com/vault/index.php?action=downloadfile&filename=chrono… and the documentation is online on the sandbox http://svn.boost.org/svn/boost/sandbox/chrono/libs/chrono/doc/html. For the moment I'm not able to test it on Windows and Mac platforms. Could you check if there are some regressions on Windows or on Mac platforms? Of course, any comments or suggestions are welcome. If there is a volontary review manager that can start inspecting the library s/he is also welcome :). This library is based on the Beman's boostified version of the probe of concept of Howard. Many thanks to Howard the originator of the library and to Beman to start the boostification. Next follows the contents of the library and the updates of the new version Version 0.1.0, April 29, 2009 Beman's boostified version Features: * The C++0x Standard Library's class common_type. * The C++0x Standard Library's compile-time rational arithmetic. * The C++0x Standard Library's time utilities, including: * Class template duration * Class template time_point * Clocks: * system_clock * monotonic_clock * high_resolution_clock * Class template timer, with typedefs: * system_timer * monotonic_timer * high_resolution_timer * Process clocks and timers: * process_clock, capturing real, user-CPU, and system-CPU times. * process_timer, capturing elapsed real, user-CPU, and system-CPU times. * run_timer, convenient reporting of process_timer results. Version 0.2.0, December 8, 2009 + New Features + Bug fixes + Updated documentation Features: * Added ratio construction and assignment from an equivalent ratio (LWG 1281. CopyConstruction and Assignment between ratios having the same normalized form) * Added nested ratio typedef type (LWG 1281. CopyConstruction and Assignment between ratios having the same normalized form) * Added BOOST_CHRONO_HAS_CLOCK_MONOTONIC macro to state if monotonic_clock is provided on a platform. * Added duration operator% (LWG 934. duration is missing operator%) * Complete duration operator* and operator/ Implementation: * Use INTMAC_C to name intmax_t constants instead of LL. * Separate chrono.cpp on # files win/chrono.cpp, mac/chrono.cpp and posix/chrono.cpp to make easier the maintenance on different platforms. * Separate process_clock.cpp on # files win/process_clock.cpp, mac/process_clock.cpp and posix/process_clock.cpp to make easir the maintenace on different platforms. * Added the error_code prototype for monotonic_clock::now for mac/chono.cpp * Fully implement mac/chrono.cpp with error handling. * Take care on POSIX systems when CLOCK_MONOTONIC is not defined. Documentation: * The documentation is written now using quick-book using as base "N2661 - A Foundation to Sleep On". Fixed Bugs * operator/ was ambiguous: Disambiguate duration operator/ * CLOCK_MONOTONIC is not defined with cygwin/gcc 3.4: Disable code when BOOST_CHRONO_HAS_CLOCK_MONOTONIC is not defined. * result of metafunctions ratio_multiply and ratio_divide were not normalized ratios: Use of the nested ratio typedef type on ratio arithmetic operations. * Copy constructor from similar duration masked the defaulted operations: Added duration defaulted implementations Note that the comon_type class should be integrated by Boost.TypeTraits, class ratio will be proposed as a standalone library Boost.Ratio, and the Timer and Process clock part could be proposed as an update of Boost.Timer. Best regards, _____________________ Vicente Juan Botet Escribá

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multi-index/interprocess find key must be allocated in shared memory?
by Jerry Hicks 11 Dec '09

11 Dec '09

Hi, I have a multi_index set working nicely in shared memory but I'm trying to figure out how to search one of my indices without allocating the search key in shared memory. Assuming my index is based on a char_string (basic_string with a segment manager allocator), is there an easy way to perform a find() operation that can use a const char *key? Trying to avoid the rather substantial overhead of instantiating my const char *key as a char_string in shared memory. Any other suggestions how I might organize things to avoid the situation would be welcomed.. Cheers, Jerry Hicks

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