Passes the name of an image to be activated in a child process.
    This function is nonreentrant.

    Format

      #include  <unistd.h>

      int execl  (const char *file_spec, const char *arg0, . . . ,
                 (char *)0); (ISO POSIX-1)

      int execl  (char *file_spec, . . . ); (Compatibility)