Re: [Boost-users] boost::mutex over a socket

On Mon, Mar 14, 2011 at 4:24 PM, Marco Piacentini wrote:

Ok...I've done something like this:

void executeThread() {   m_mutex.lock();   length=boost::asio::read(socket_,boost::asio::buffer(msg,sizeof(msg)), ec);   m_mutex.unlock();

  m_mutex.lock();  boost::asio::write(socket_,boost::asio::buffer(msgToSend,sizeof(msgToSend)));   m_mutex.unlock(); }

and I call two thread inside a member's function Server Class:

void handle_accept() {     ....     ....

  if(fork()==0)  {         boost::thread thread_read(&server::executeThread,this);         boost::thread thread_write(&server::executeThread,this);         thread_read.join();         thread_write.join();  }  else {         ....         .... }

}

Can I obtain in this way a thread that read and the other that write? and to obtain a ciclyc behaviour, where I have to put the for(;;)?thanks..

________________________________ Da: Kulti A: boost-users@lists.boost.org Inviato: Lun 14 marzo 2011, 16:59:39 Oggetto: Re: [Boost-users] boost::mutex over a socket

On Mon, Mar 14, 2011 at 3:28 PM, Marco Piacentini wrote:

...

Hi guys...I've 2 thread and I would like that one of these performs a synchronous read, menawhile the other performs a synchrounous write...adn obviously they share the same socket.....the signature of the functions are the following:

length=boost::asio::read(socket_,boost::asio::buffer(msg,sizeof(msg)), ec);

boost::asio::write(socket_,boost::asio::buffer(msgToSend,sizeof(msgToSend)));

socket_ is a private field of the classe Server.

How can I use the mutex to perform concurrently and safetly these operations?

Thanks..

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The typical usage of mutex: 1. Add boost::mutex mutex_ as private field of class Server 2. When you read/write just add mutex_.lock() before and mutex_.unlock() after. Also you can use boost::mutex::scoped_lock if it's convenient. _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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At first, I cannot understand why you try to use one handler for different threads? If you wanna get two threads (one for read and one for write) you need two different handlers. At second, If you do fork - you get two processes, which cannot share mutex. If you need to interprocess synchronization you should use other mechanisms, e.g. lock-file.