Start the given program progname.
This is a restart of OWBasic. No variables of the old program are available in the newly started program. Program is searched in "program category" or category cat if given. If showmsg is FALSE, the compiler does not show the compiling message. You can give program parameters to the program to be started with param; the parameter is stored in the global variable PARAMETER$.
If return is true, the calling program is started again after the called program has ended. The name of the called program is given as parameter.