November 2009 - Boost-users - lists.preview.boost.org

program_options hierarchical options
by Yang Zhang 09 Nov '09

09 Nov '09

Is there an example of using program_options to build a hierarchical options parser (a la svn, apt-get, git, etc.), in which earlier options select parsers for later options? -- Yang Zhang http://www.mit.edu/~y_z/

2 3

[interprocess] Performance problem with managed_shared_memory
by Moritz 09 Nov '09

09 Nov '09

Hi there, I have a performance problem using the managed_shared_memory and the interprocess_vector. I attached a minimalistic, compilable example that demonstrates this. I create a vector that contains a simple class and I write into this vector. If the vector is located in the shared_memory this takes much longer than if it is located in the process-local memory. The main difference then is the used allocator. But I can not explain it. If I run the attached code, I get the following results: (running on Ubuntu 8.10, Boost version 1.40, gcc-Version 4.3.3) SHMEM_TESTING: Mean: 0.024768 seconds. else Mean: 0.015022 seconds. I do not understand where the difference results from. Is there anybody who has an explanation for that? #include <boost/interprocess/containers/vector.hpp> #include <boost/interprocess/allocators/allocator.hpp> #include <boost/interprocess/managed_shared_memory.hpp> #include <boost/thread/xtime.hpp> #include <iostream> #include <vector> namespace ipc = boost::interprocess; double get_timestamp() { boost::xtime timestamp; boost::xtime_get(&timestamp, boost::TIME_UTC); return timestamp.sec + ((double)timestamp.nsec / 1000000000.0); } class Point3f { public: double x; double y; double z; }; #define VECTOR_ELEMENTS 500000 int main() { #define SHMEM_TESTING #ifdef SHMEM_TESTING ipc::shared_memory_object::remove("shmem"); ipc::managed_shared_memory managed_shm( ipc::create_only, "shmem" , VECTOR_ELEMENTS*3*sizeof( double ) + 1024 ); typedef ipc::managed_shared_memory::segment_manager segment_manager_t; typedef ipc::allocator<void, segment_manager_t> void_allocator; typedef ipc::allocator<Point3f, segment_manager_t> Point3fAllocator; typedef ipc::vector<Point3f, Point3fAllocator> Point3fVector; void_allocator alloc( managed_shm.get_segment_manager() ); Point3fVector * vec = managed_shm.construct<Point3fVector>( ipc::unique_instance )( alloc ); if ( !vec ) return -1; #else ipc::vector<Point3f> * vec = new ipc::vector<Point3f>(); // std::vector<Point3f> * vec = new std::vector<Point3f>(); #endif for ( unsigned int i = 0; i < VECTOR_ELEMENTS; ++i ) { vec->push_back( Point3f() ); } double sum = 0; unsigned int count = 0; for ( ; count < 20; ++count ) { double t1 = get_timestamp(); for ( unsigned int i = 0; i < vec->size(); ++i ) { ( *vec )[i].x = i; ( *vec )[i].y = i; ( *vec )[i].z = i; } sum += get_timestamp() - t1; } std::cerr << std::fixed << "Mean: " << sum/static_cast<double>(count) << " seconds." << std::endl; return 0; }

2 2

Re: [Boost-users] boost thread on x64
by Pascal Kesseli 08 Nov '09

08 Nov '09

Hi again In another attempt to compile my code using boost-thread headers, unfortunately none of the suggested preprocessor definitions worked. Does anyone see a possibility to make boost mingw64 compatible? Thx and best regards Pascal

2 1

Avoiding reinventing the wheel for a public api with binary compatibility in mind
by Geoff Hilton 08 Nov '09

08 Nov '09

I'm writing a public api for a product which will be bundled as a precompiled dll or binary and one of my goals is binary compatibility (if not across major versions, at least across minor). I'd like to implement the pimpl idiom and reference counting for the handle classes as appropriate, but I'm worried about all the typical stuff (exception safety, memory leaks, etc) and I'd rather not reinvent the wheel. eg. template<typename T> class MyClass { public: T foo(); private: boost::shared_ptr<MyClassImpl<T> > impl; }; Using boost::shared_ptr would be great, but this means clients of my code would have to have the same version of boost installed that we use, and I imagine this could cause conflicts in the event that they happen to use boost (and a different version of it). I'd rather not include more code dependencies than I absolutely have to, especially if they may prove problematic in the future. What do I do? I know I'm not the first in this situation. How often have others opted for this dependency as opposed to furnishing their own alternative that would avoid additional dependencies (at the expense of the benefit of time-tested code)?

5 10

[variant] Length of variant
by Seweryn Habdank-Wojewódzki 08 Nov '09

08 Nov '09

Hi, According to Karlsson boost::variant is limited to 11 elements. Is there any option to extend that? What are the real limitations for the VS 9.0 and GCC 4.0? If number might be extended what might happen e.g. during compilation? Is the size somewhere defined once or is spread in all the code of variant? Best regards, Seweryn Habdank-Wojewodzki.

3 2

ASIO or Thread
by Lloyd 08 Nov '09

08 Nov '09

Hi, We need to develop a server in a LAN environment, in which the number of connections at a time will be less, but the data traffic per connection will be huge (gigabytes). So for the best performance which library is better? ASIO or Thread? Is thre is any specif advice for attaining the maximum performace (data rate)? I am a newbie. Thanks, Lloyd ______________________________________ Scanned and protected by Email scanner

6 5

tons of errors because boost::thread::thread() in thread/detail/thread.hpp is private
by tiredashell 08 Nov '09

08 Nov '09

I am successfully using Boost.Thread on Windows without a hitch, but when porting my program to OSX I get the following compile error, followed by an enormous chain of errors that probably are a derivative of it: ./boost/thread/detail/thread.hpp:108: error: ‘boost::thread::thread(boost::thread&)’ is private When checking the class that it mentioned, it appears that it is in fact declared as private for some reason. Is there a reason I'm only receiving this error on OSX, and how can it be fixed?

2 2

[Boost Asio] Newtork Programming
by Boost lzw 08 Nov '09

08 Nov '09

Folks, I want to start learning network programming + socket programming so that I can understand Boost.Asio and beyond it. Any good books for beginners or online resources to recommend? I have MSVS 2008 Profssional on Windows XP Professional installed on my PC. Thanks in advance, Robert

2 1

Building Boost on Snow Leopard (with Xcode 3.2 installed)
by Manfred Schwind 07 Nov '09

07 Nov '09

Hi, I'm trying to build boost 1.40 on Mac OS X 10.6 Snow Leopard (with Xcode 3.2 is installed). This is the command I used to use on Mac OS X 10.5 Leopard and Xcode 3.1.x: bjam --prefix=/somepath --layout=versioned toolset=darwin architecture=combined address-model=32_64 link=static install This used to give me great universal binaries (ppc/intel, 32-/64-bit). But since installing Snow Leopard and Xcode 3.2 it does not build anymore. No binaries are created and I get strange compiler errors like this: /usr/include/time.h:77: error: expected constructor, destructor, or type conversion before ‘typedef’ /usr/include/time.h:124: error: ‘clock_t’ does not name a type In file included from /usr/include/c++/4.2.1/cwchar:52, from /usr/include/c++/4.2.1/bits/postypes.h:46, from /usr/include/c++/4.2.1/iosfwd:49, from /usr/include/c++/4.2.1/bits/stl_algobase.h:70, from /usr/include/c++/4.2.1/bits/char_traits.h:46, from /usr/include/c++/4.2.1/string:47, from ./boost/program_options/errors.hpp:12, from ./boost/program_options/options_description.hpp: 12, from libs/program_options/src/ options_description.cpp:10: I _assume_ the problem is gcc 4.2 that was probably installed by Xcode 3.2. I am also not sure if gcc 4.2 even supports PCC code generation. So is there a way to switch to gcc 4.0? Or any other solution for the problem? I tried toolset=gcc-4.0 instead of darwin. This resulted in some binaries, but they are not universal anymore, as far as I can see. Any ideas/hints how to successfully build boost on Snow Leopard? Thank you very much, Mani -- http://mani.de - friendly software iVolume - listen to music freehand LittleSecrets - the encrypted notepad Sahara - sand in your pocket Watchdog - baffle the curious

6 7

Library failing
by Mathew Benson 07 Nov '09

07 Nov '09

I wrote a utility to abstract sending a data buffer to a central server with a single function call. I verified it works, and then split out the functionality into a library (.lib). I tried using it in a test application, but keep getting an "Access violation reading location 0x00000000" error. It occurs in the call: socket_.async_receive_from( boost::asio::buffer(data_, max_length), sender_endpoint_, boost::bind(&CommIn::handle_receive_from, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); I'm using Visual C++ 2005 Express, and a UML to C++ modeler and code generator called Rhapsody. I'm not sure where to even begin troubleshooting this.

3 5