       execl ?-argv0 argv0? prog ?arglist?
              Do  an execl, replacing the current program (either
              Extended Tcl or an application  with  Extended  Tcl
              embedded  into  it) with prog and passing the argu
              ments in the list arglist.

              The -argv0 options specifies that argv0  is  to  be
              passed to the program as argv [0] rather than prog.

              Note: If you are using execl in  a  Tk  application
              and it fails, you may not do anything that accesses
              the X server or you will receive a BadWindow  error
              from  the X server.  This includes executing the Tk
              version of the exit command.  We suggest using  the
              following command to abort Tk applications after an
              execl failure:

                  kill [id process]

              On Windows 95/NT, where the  fork  command  is  not
              available,  execl  starts a new process and returns
              the process id.
