#include <sys/types.h>
#include <sys/wait.h>
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
    
    int main(int argc, char *argv[])
    {
      int status;
      int pid;
      char *prog_arv[4];

      /* 
       * Build argument list
       */

      prog_argv[0] = "/usr/local/bin/ls";
      prog_argv[1] = "-l";
      prog_argv[2] = "/";
      prog_argv[3] = NULL;

      /*
       * Create a process space for the ls  
       */
      if ((pid=fork()) < 0)
      {
        perror ("Fork failed");
        exit(errno);
      }

      if (!pid)
      {
        /* This is the child, so execute the ls */ 
        execvp (prog_argv[0], prog_argv);
      }

      if (pid)
      {
        /* 
         * We're in the parent; let's wait for the child to finish
         */
        waitpid (pid, NULL, 0);
      }
    }