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Conference turris::decladebug

Title:	Digital Ladebug debugger

Moderator:	TLE::LUCIA

Created:	Fri Feb 28 1992
Last Modified:	Fri Jun 06 1997
Last Successful Update:	Fri Jun 06 1997
Number of topics:	969
Total number of notes:	3959

867.0. "Why omit variables that start with __?" by DECC::MJHANS (Matthew Hanselman, DEC C) Wed Mar 05 1997 15:04

    ladebug 4.0-30:
    
    Why does ladebug refuse to print out structure members when they begin
    with two underscores?  Interestingly, this only happens for C++ -- if
    the exact same program is compiled for C, it works fine.
    
    							- Matt
    
    =================
    struct A {
      int __b;
    } c;
    
    main() {}
    =================
    
    % ladebug a.out
    Welcome to the Ladebug Debugger Version 4.0-30
    ------------------ 
    object file name: a.out 
    Reading symbolic information ...done
    (ladebug) whatis A
    struct A  {
    }

T.R	Title	User	Personal Name	Date	Lines
867.2		ADA9X::BRETT		`Wed Mar 05 1997 16:02`	4
	I believe this is to deliberately conceal the compiler-generated entities that we add to the classes etc. /Bevin
867.3		DECC::OUELLETTE		`Wed Mar 05 1997 16:07`	3
	This sort of deliberate obfuscation is little help to the average user. A naive user may appreciate it, but it will really annoy and confuse a power user.
867.4		TLE::LUCIA	http://asaab.zko.dec.com/~lucia/biography.html	`Wed Mar 05 1997 17:26`	7
	Hence the STWG problem of "compiler: should we (debugger) print this symbol or not?" Only the compiler knows. It would be great if it would tell us. Tim
867.5		ADA9X::BRETT		`Thu Mar 06 1997 08:05`	10
	> Only the compiler knows. It would be great if it would tell us. Only the USER knows whether they are trying to debug some memory trashing of a __vptr, or just trying to see the normal language data members of their struct. So the compiler can flag the 'implicit' components - which we do today by '__'ing their identifiers - but only the user and the debugger can decide whether or not to see/show them. /Bevin
867.6	$verbose	TLE::MERRITT	Steve Merritt, Ladebug Team	`Fri Mar 07 1997 10:11`	16
	It gives alot of extra stuff you may not want, but isn't this the purpose for $verbose? (ladebug) set $verbose=1 (ladebug) whatis u class Uscore { long x; short _t; int __f; Uscore(Uscore* const); Uscore(Uscore* const, const Uscore&); void foo(Uscore* const); Uscore& operator =(Uscore* const, const Uscore&); } u
867.7	I concede	DECC::MJHANS	Matthew Hanselman, DEC C	`Fri Mar 07 1997 11:06`	5
	I can see the motivation for it more now, esp with the $verbose variable. I didn't realize there was so much "questionably unuseful" information there was. :) - Matt
867.8		DECC::OUELLETTE	crunch	`Fri Mar 07 1997 11:12`	4
	> set $verbose=1 Way cool. Is there a way for me to just see the data members and ignore the member functions?
867.9	I don't think so...	TLE::MERRITT	Steve Merritt, Ladebug Team	`Fri Mar 07 1997 13:17`	10
	>Way cool. Is there a way for me to just see the data members >and ignore the member functions? (ladebug) set $verbose=0.5 =8^) Unfortunately no, to my knowledge there is no way to limit the output when using $verbose. -Steve