Fork() and wait() UNIX System Call

#include  <stdio.h>

#include  <stdlib.h>

#include  <sys/types.h>

int spawn (char* program, char** arg_list)

{

  pid_t child_pid;

  child_pid = fork ();

  if (child_pid != 0)   

     return child_pid;

  else {    

     execvp (program, arg_list);    

     fprintf (stderr,"an error occurred in execvp\n");

     abort ();

  }

}

int main ()

{

  int child_status;

  char* arg_list[] = { "ls",  "-l",  "/",  NULL  };

   spawn("ls", arg_list);

  wait (&child_status);

  return 0;

}

Output:

 drwxr-xr-x   2 root root  4096 Sep 12  2009 bin

drwxr-xr-x   4 root root  1024 Sep 12  2009 boot

drwxr-xr-x  11 root root  3620 Mar 17 15:33 dev

drwxr-xr-x  93 root root 12288 Mar 17 15:33 etc

drwxr-xr-x 115 root root  4096 Feb  9 20:26 home

drwxr-xr-x  14 root root  4096 Sep 12  2009 lib

drwx------   2 root root 16384 Sep 12  2009 lost+found

drwxr-xr-x   2 root root  4096 Sep 12  2009 media

drwxr-xr-x   2 root root     0 Mar 17 15:32 misc

drwxr-xr-x   2 root root  4096 Oct 11  2006 mnt

drwxr-xr-x   2 root root     0 Mar 17 15:32 net