Pipes between child processes in C

Question

I\'ve seen this question before, but still a bit confused: how would I create communication between child processes of the same parent? All I\'m trying to do at the moment i

Answer 1

In a simplified non-exec case, you should do something like.

#define nproc 17

int pipes[nproc - 1][2];
int pids[nproc];

int i;
for( i = 0; i < nproc - 1; i++ ) {
    pipe( pipes[i] );
}

int rank;
for( rank = 0; rank < nproc; rank++ ) {
    pids[rank] = fork();
    if( !pids[rank] ) {
        if( rank == 0 ) {
            write( pipe[rank][1], /* your message */ );
        }

        read( pipe[rank-1][0], /* read the message somewhere*/ );

        if( rank < nproc - 1 ) {
            write( pipe[rank][1], /* write the message to the next child process*/ );
        } else {
            // Here print the received message (it's already received above)
        }
    }
}

for( rank = 0; rank < nproc; ++rank ) {
    wait( pids[rank] );
}