Path: utzoo!mnetor!uunet!husc6!bbn!uwmcsd1!ig!agate!ucbvax!RCCA.BBN.COM!RMCEWEN
From: RMCEWEN@RCCA.BBN.COM (Regis McEwen)
Newsgroups: comp.os.vms
Subject: re: question on chaining images
Message-ID: <8803141534.AA28168@ucbvax.Berkeley.EDU>
Date: 14 Mar 88 03:42:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 35

>>	I am looking for a system service or run-time library routine that
>>	will allow me to execute a second image.  I want to do this in such a
>>	way that the flow of control will pass entirely to the second image,
>>	and will return to the first image at the calling point after the
>>	second image completes. Neither CREPRC nor LIB$SPAWN seem to do this,
>>	which makes sense since their purpose is to create another process
>>	altogether.  I just want the SAME process to start executing a second
>>	image.  I'm sure I'm overlooking something obvious...

>LIB$DO_COMMAND
>LIB$RUN_PROGRAM
>							-- Jerry


	Neither one of these RTL routines will accomplish what you
	want.

	LIB$DO_COMMAND/LIB$RUN_PROGRAM will execute the command/program,
	respectively, then stop, immediately, *never* returning you to
	the calling program unless there was an error executing the call.
	(Assuming, of course, you have appropiate error handling).

	This is documented in the RTL manual.

	$CREPRC/LIB$SPAWN will do this, but, as you pointed out, will create
	another process, sub-process or possibly detached if you specify
	a UIC in $CREPRC.

	What you want *used* to be available with pre-VMS V3.? called
	LIB$EXECUTE_CLI.

	The only other "unsupported" way to do this, is to build your own
	calling stack and make a call to SYS$CLI.

							-Regis