Unix fork-exec technique

fork_exec.c

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

void fork_exec(void)
{
    switch (fork())
    {
        case -1:    // Error
            perror("fork");
            exit(EXIT_FAILURE);
        case 0:     // Child
            char *argv[] = {"ls", "-ls", NULL};
            execvp("ls", argv);
            perror("exec");
            exit(EXIT_FAILURE);
        default:    // Parent
            waitpid(-1, NULL, 0);
    }
}