Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.3 4.3bsd-beta 6/6/85; site ucbvax.BERKELEY.EDU
Path: utzoo!decvax!bellcore!ulysses!ucbvax!info-vax
From: info-vax@ucbvax.UUCP
Newsgroups: mod.computers.vax
Subject: Re: Getting tracebacks without signalling
Message-ID: <8602071038.AA10846@seismo.CSS.GOV>
Date: Fri, 7-Feb-86 17:30:41 EST
Article-I.D.: seismo.8602071038.AA10846
Posted: Fri Feb  7 17:30:41 1986
Date-Received: Sun, 9-Feb-86 07:41:21 EST
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The ARPA Internet
Lines: 58
Approved: info-vax@sri-kl.arpa

[]

The following condition handler and message definition file should allow you
both to see a traceback and to do an unwind.  VMS V4 kindly displays the
original error message when it comes to HANDLE in the traceback.  With
previous versions of VMS, it was necessary to call SYS$PUTMSG to see the
cause of the original error.


	INTEGER*4 FUNCTION HANDLE( SIGARGS, MECHARGS )

	IMPLICIT INTEGER(A-Z)
	INTEGER*4 SIGARGS(2), MECHARGS(5)

	INCLUDE '($SSDEF)'
	INCLUDE '($STSDEF)'

	EXTERNAL FAC_TRABACFOL

	IF ( ( SIGARGS(2) .AND. STS$M_SEVERITY ) .LT. 4 ) THEN

C  For all except severe errors, use default handler to print traceback
C  and continue

	    HANDLE = SS$_RESIGNAL

	ELSE

C  Severe error ...
C  We signal a warning to get a traceback (from here).

	    CALL LIB$SIGNAL( FAC_TRABACFOL )

C  Now unwind to the caller of the establisher of this handler

	    CALL SYS$UNWIND( , )

	ENDIF

	RETURN
	END

*****

.TITLE	FACMSG.MSG	Message definition

.FACILITY	FACIL		101	/PREFIX=FAC_
!		^^^^^		^^^	        ^^^	Replace as appropriate

TRABACFOL/W	"error has occurred - traceback follows"

.END

--
Jim Richardson
Department of Pure Mathematics, University of Sydney, NSW 2006, Australia
UUCP:	...!seismo!munnari!summer.oz!jimr
ARPA:	jimr%summer.oz@seismo.arpa		CSNET:	jimr@summer.oz