gistfile1.c

#include <stdio.h>
#include <unistd.h>

int main(int argc, char *argv[]) {
    int status;
    int parent_pid = getpid();
    int child_pid = fork();
    if(!child_pid) { // If Child
        printf("child\n");
        char * send_buffer;
        send_buffer = (char*) malloc(6);
        send_buffer = "Hello";
        long returnval = syscall(292, parent_pid, sizeof(char*) * 6, send_buffer);
        printf("Child: return val %d\n", returnval);
        printf("Child: Message sent.\n");
        return 0;
    } else { // If Parent
        waitpid(child_pid, &status,0);
        char * recv_buffer;
        recv_buffer = (char*) malloc(6);
        long returnval = syscall(293, child_pid, sizeof(char*) * 6, recv_buffer);
        printf("Parent: return val %d\n", returnval);
        printf("Parent: Message received - %s\n", recv_buffer);
        return 0;
    }
}