CODEWITHSUNDEEP
c++socketsg++
Kolyunya
Kolyunya

Reputation: 6240

C++ write to a socket causes the program to end

I'm making a socket server which has 2 threads, each running in a loop. The first looks for new connections and the second reads data from sockets which are already connected and replies to them. The problem is in the second one. 'write' function breaks the loops somehow and causes the program to finish... No errors occur... That is the problem.

The following code is a 2nd thread's function. If I don't write anything to a socket, the program runs well

void* SocketServer::threadSocketsRead( void* thisServer )
{
    SocketServer*               server; 
    int                         key,
                                playersNumber,
                                requestLength;
    Player*                     player;
    char                        message[256];
    string                      reply;

    server = (SocketServer*)thisServer;

    while ( 1 )
    {
        playersNumber = server->players.size();
        for ( key = 0 ; key < playersNumber ; key ++ )
        {
            player = server->players[key];  
            requestLength = read ( player->socket , (void*)&message , 255 );
            if ( requestLength < 0 )
            {
                perror ( "read" );
            }
            else
            {
                /*
                    If I uncomment the line, it will write data to
                    the socket and finish the whole program.

                    If I do no uncomment it, the programs runs in a loop further.
                */

                //int result = write ( player->socket , "reply\0" , 6 );
            };
        }
        sleep(1);
    }
}

Upvotes: 1

Views: 155

Answers (1)

cnicutar
cnicutar

Reputation: 182619

You're probably writing to a dead socket and getting a SIGPIPE who's default action is to terminate the program. You can:

  • Handle the SIGPIPE
  • Pass MSG_NOSIGNAL to send(2)
  • Set SO_NOSIGPIPE using setsockopt (it's not portable)

Upvotes: 3

Related Questions