CODEWITHSUNDEEP
c++socketsposix-select
user3100708
user3100708

Reputation: 148

Select in socket c++ doesn't work

I created a class that implements the select function of the tcpsocket. (listenSock is a vector of TcpSocket - that works) I dont understand why but the second time select is called the program stop working.

TCPSocket* MultipleTCPSocketsListener::listenToSocket(){
    //TODO: create local set for the select function (fd_set)
    fd_set set;
    FD_ZERO (&set);
    FD_SET (0, &set);

    //TODO: fill the set with file descriptors from the socket list using (FD_SET macro)
    for ( int i = 0; i < listenSock.size(); i++ )
    {
        FD_SET (listenSock.at(i)->getSock(), &set);
    }

    //TODO: perform the select
    int sel=select(sizeof(set)*8,&set,NULL,NULL,NULL);

    //TODO: check the returned value from the select to find the socket that is ready
     if (sel==-1) {
          perror("select failed");
          return NULL;
     }

    //TODO: if select return a valid socket return the matching TCPSocket object otherwise return NULL
     if (sel > 0)
     {
         for ( int i = 0; i < listenSock.size(); i++ )
         {
             if (FD_ISSET(listenSock.at(i)->getSock(), &set)) return  listenSock.at(i);
         }
     }
    return NULL;
}

Upvotes: 2

Views: 659

Answers (1)

Hans Kl&#252;nder
Hans Kl&#252;nder

Reputation: 2292

FD_SET (0, &set);

is useless. You instruct select to treat stdin as one of the sockets to watch.

Upvotes: 0

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