November 2009 - Boost-users

[config] disabling _MSC_EXTENSIONS disables win32
by Igor R 11 Nov '09

11 Nov '09

Hello, In visualc.hpp I found the following: #if !defined(_MSC_EXTENSIONS) && !defined(BOOST_DISABLE_WIN32) # define BOOST_DISABLE_WIN32 #endif I.e., disabling MSVC-specific exnetions (/Za) disables also WIN32, which, in turn, leads to undefined BOOST_WINDOWS. So if I try to compile my project with /Za, nothing compiles, because there're lot of places where BOOST_WINDOWS is used to select platform-dependant implementation (eg., in ASIO). But if I understand correctly, the purpose of disabling MSVC *language* extenstions is to ensure that the code is portable & standard-complient. So it seems to be incorrect to imply from this BOOST_DISABLE_WIN32. Am I wrong? Thanks.

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doubt on lambda expression
by Emanuele Rocci 11 Nov '09

11 Nov '09

Hi AllI started playing with boost::lambda and I need some help or some clarification about itor some hint to better understanding how does it work. I have this piece of code using namespace boost::lambda;using boost::lambda::var; int main(int argc, char** argv) { std::vector< int > myList; myList.push_back(100); myList.push_back(200); int interval = 20; std::for_each( myList.begin(), myList.end(), ( std::cout << "value: " << _1 << "\n", std::cout << "interval: " << var( interval ) << "\n", var( interval )++ ));} I understood that writing a lambda expression would be a substitutefor writing a functor. I expected the following result value: 100interval: 20value: 200interval: 21 Instead I had the following intervalfirst value: 1002020021 Why the strings "interval" and "first" are not written for each value and how can I achieve this?Kind RegardsMn _________________________________________________________________ Più di 30 Web Radio: le trovi su Messenger http://www.messenger.it/radioMessenger.aspx

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Thread Checking Tools
by Alexander Gray II 11 Nov '09

11 Nov '09

Hi, What thread checking tool (if any) is being used to ensure the boost threading model is doing the right thing? I'm currently evaluating various tools, and non of them really support this threading model. For instance, when I run the Boost threading examples through Intel Thread Checker, I get a bunch of "errors" from the tool. Someone else ran across this, and Intel's response was pretty much "we don't support Boost Threading Model": http://software.intel.com/en-us/forums/intel-parallel-studio/topic/68875/ along with same response from Microsoft CHESS: http://social.msdn.microsoft.com/Forums/en-US/chess/thread/3be2348f-661a-4f… I evaluated "helgrind" and "drd", but our suppression files were getting so large, the poor tool couldn't handle it. Any ideas how I can verify our application is truly thread safe if we use Boost? Thanks, -alex-

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Rading data from streambuf
by Lloyd 11 Nov '09

11 Nov '09

Hi, How can we read data from a streambuf? I am using boost asio. My code is as follows- boost::asio::streambuf stream; boost::asio::async_read_until(Socket, stream,string("\r\n"), boost::bind(&TCPConnection::HandleRead, shared_from_this(), boost::asio::placeholders::error)); .... .... How can i get the data from "stream" as a "char *buffer" or as a "string" Thanks, Lloyd ______________________________________ Scanned and protected by Email scanner

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concatenate strings?
by pedro chaparro 11 Nov '09

11 Nov '09

hi, i'm wondering if there is some function into boost to concatenate several strings to have just a long one? thanks -- Ing Pedro Alonso Chaparro Valero Ciudad Politecnica de la Innovación iTEAM - Mobile Communications Group Polytechnic University of Valencia C\ Camino de Vera S/N, Edificio 8G 46022 Valencia, Spain

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Constructing a shared pointer from a const pointer
by veerus 11 Nov '09

11 Nov '09

Hi All, I have been in trouble for a day solving this seemingly simple problem - constructing shared_ptr<X> from const X& without copying the X object. The programming logic does not allow me to construct the shared_ptr like this: SX x = SX( new X( x ) ); Consider the following piece of code: void foo( const X& x ) { typedef shared_ptr<X> SX; SX px = SX( &x ); bar( px ); } The compiler gives the following error: In shared_ptr.hpp at line 184: 'initializing' cannot convert from 'const X *' to 'X*'. Please suggest any procedure to solve this problem. -- View this message in context: http://old.nabble.com/Constructing-a-shared-pointer-from-a-const-pointer-tp… Sent from the Boost - Users mailing list archive at Nabble.com.

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BGL - parallel/distributed
by Ondrej Sluciak 11 Nov '09

11 Nov '09

Does anybody know how to use the functions in graph/parallel and graph/distributed? I couldn't find any references in documentation to parallel/distributed processing in graph lib, though there is obviously such functionality. Is it the same implementation as in Parallel BGL project (http://www.osl.iu.edu/research/pbgl/)? I must say that the documentation of graph library desperately needs an update.

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[Asio] Is shared_ptr with async_send_to ok?
by Dylan Klomparens 11 Nov '09

11 Nov '09

I'm using a UDP socket to send data asynchronously. I know I need to preserve the data in a buffer until the async write is complete. Can I use a shared_ptr to accomplish this? Basically, my question is, will async_send_tokeep a copy of my shared_ptr so that the data doesn't get deleted? Do I need to use a particular overload of the boost::asio::buffer function to ensure that a copy of the shared_ptr is stored? Here is an example: boost::asio::streambuf Buffer; // ... buffer is filled with data ... int BufferSize = Buffer.size(); boost::shared_ptr<unsigned char> SharedBuffer(new unsigned char [BufferSize]); Buffer.sgetn(*SharedBuffer, BufferSize); Buffer.consume(BufferSize); Socket.async_send_to(boost::asio::buffer(*SharedBuffer, BufferSize), DestinationEndpoint, boost::bind(&MyClass::OnPacketSent, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); // Shared buffer goes out of scope here, immediately!

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Boost.Asio: "End of file" when receiving data
by tiredashell 11 Nov '09

11 Nov '09

In addition to the "parameter is incorrect" error which I inquired about earlier (and remains unsolved), I am getting "End of file" sometimes when I attempt to receive data such as in the code below. Please offer some guidance as to its cause, because there is absolutely no documentation on what either of these errors mean. char reply[1024]; boost::system::error_code error; size_t reply_length = s.receive(boost::asio::buffer(reply, 1024), 0, error); if (error) cout << error.message() << endl;

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running a server "in background mode" ??
by pedro chaparro 11 Nov '09

11 Nov '09

Hi, i need to use a server inside of other code application, i take the example from http://www.boost.org/doc/libs/1_40_0/doc/html/boost_asio/tutorial/tutdaytim… and it works but the server stay in listening mode and there is other code after that i'd like continue executing, is possible tu run the server let's say like in a background mode? thanks -- Ing Pedro Alonso Chaparro Valero Ciudad Politecnica de la Innovación iTEAM - Mobile Communications Group Polytechnic University of Valencia C\ Camino de Vera S/N, Edificio 8G 46022 Valencia, Spain

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