Path: utzoo!utgpu!attcan!uunet!husc6!mailrus!uwmcsd1!ig!agate!ucbvax!CITHEX.CALTECH.EDU!carl
From: carl@CITHEX.CALTECH.EDU
Newsgroups: comp.os.vms
Subject: VAX C/DEBUGGER bug
Message-ID: <880808092931.22b@CitHex.Caltech.Edu>
Date: 8 Aug 88 16:29:31 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 59

I just noticed a bug somewhere within the interaction between VAX C and
the DEBUGGER.  The problem is that the DEBUGGER won't allow you to examine
character arrays using the EXAMINE/ASCIZ command.  The following command
procedure demonstrates the bug.  Does anybody know whether:
	1)  The bug's been SPR'd; and
	2)  Whether it goes away with VMS v5.0?
It was introduced sometime after VMS V4.5 and VAX C V2.1-007 and is there under
VMS V4.7 and VAX C V2.3-024.
********************************************************************************
	$	CREATE C_DEBUG_BUG.C	!	'F$VERIFY(1)
	main()           
	{	char test[20], *ptr;
		strcpy(test,"Testing");
		ptr = test;
		puts(ptr);
		puts(test);
	}
	$	CC/DEBUG/NOOPT C_DEBUG_BUG
	$	LINK C_DEBUG_BUG,SYS$INPUT:/OPT/DEBUG
	SYS$SHARE:VAXCRTL/SHARE
	$	RUN C_DEBUG_BUG
	SET BREAK %LINE 5
	GO
	EXAM/ASCIZ test
	EXAM/ASCIZ *test
	EXAM/ASCIZ ptr
	EXAM/ASCIZ *ptr
	EXIT
	$	DELETE C_DEBUG_BUG.C;,.OBJ;,.EXE;
********************************************************************************
The relevent debugger output from VMS V4.5 and VAX C V2.1-007 is:
********************************************************************************
	SET BREAK %LINE 5
	GO
	break at C_DEBUG_BUG\main\%LINE 5
	     5:         puts(ptr);
	EXAM/ASCIZ test
	C_DEBUG_BUG\main\test:  "Testing"
	EXAM/ASCIZ *test
	%DEBUG-W-NOACCESSR, no read access to virtual address 00000054
	EXAM/ASCIZ ptr
	C_DEBUG_BUG\main\ptr:   "hqt."
	EXAM/ASCIZ *ptr
	*C_DEBUG_BUG\main\ptr:  "Testing"
********************************************************************************
and from VMS V4.7 and VAX C V2.3-024 is:
********************************************************************************
	SET BREAK %LINE 5
	GO
	break at C_DEBUG_BUG\main\%LINE 5
	     5:         puts(ptr);
	EXAM/ASCIZ test
	%DEBUG-E-NOACCESSR, no read access to virtual address 7FF01D68
	EXAM/ASCIZ *test
	%DEBUG-E-NOACCESSR, no read access to virtual address 00000054
	EXAM/ASCIZ ptr
	%DEBUG-E-NOACCESSR, no read access to virtual address 7FF01D7C
	EXAM/ASCIZ *ptr
	%DEBUG-E-NOACCESSR, no read access to virtual address 7FF01D68