fork-3.c

#include <stdlib.h>	/* needed to define exit() */
#include <unistd.h>	/* needed  for fork() ad getpid() */
#include <stdio.h>	/* needed for printf() */

int main (int argc, char **argv)	{
	int pid;	/* process ID */

	switch (pid = fork())	{
	case 0:		/* a fork returns 0 to the child */
		printf("I am the child process: pid=%d\n", getpid());
		break;
	
	default:	/* a fork returns a pid to the parent */
		printf("I am the parent process: pid=%d, child pid=%d\n", getpid(), pid);
		break;

	case -1:	/* something went wrong */
		perror("fork");
		exit(1);
	
	}
	
	exit(0);

}