Question

I recently started learning about IPC and I have some issues. I wrote a program that creates two processes which communicate through pipe like this:

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <unistd.h>


int main(void)
{
    int pfds[2];
    char buf[30];
    pipe(pfds);
    if (!fork()) 
    {
        printf(" CHILD: writing to the pipe\n");
        write(pfds[1], "test", 5);
        printf(" CHILD: exiting\n");
        exit(0);
    } 
    else 
    {
        printf("PARENT: reading from pipe\n");
        read(pfds[0], buf, 5);
        printf("PARENT: read \"%s\"\n", buf);
        wait(NULL);
    }
    return 0;
}

Sorry for not handling potential errors, I wrote it like this for simplicity.

This works great but my question is: Is there any possibility to have two programs – server/client(two separate executables – not parent process/child process relationship) that communicate through pipe? Just like you can through FIFOs?

Thank you!

Answer 1

A regular pipe can only connect two related processes. It is created by a process and will vanish when the last process closes it.

To communicate between two separate processes you must use named pipes (FIFO).