SHIT! (Sorry) - Procedural Types

Tue, 08 Jul 1997 00:28:02 +0800

>Now we are in trouble: I cannot reproduce this bug, neither on DJGPP, nor
>on Linux.

AARRRGGHHH! All procedures are defined in a unit! Whats worse, some test
programs refuse to compile - but only sometimes!! As I said in the original
mail, the problem is not CString or Function related - problems also occur
with procedures.

Im using the latest beta GPC for DJGPP 2.01. The following tests were
compiled from a DOS shell under Windows 3.11, but they also occur when
running in pure DOS using CWSDPMI r3.

Below is the ACTUAL (no lie) screen shot of what just happened to me!
[Including the habitual typing mistake - oops] 


<-------------- BEGIN SEENSHOT ------------------------>

E:\DJGPP\GPC\BUG>q bug02\
                 gpc bug02.pas -o bug02.exe
bug02.pas: In function `program_Bug02':
bug02.pas:16: incompatible types in assignment

E:\DJGPP\GPC\BUG>gpc bug02.pas -o bug02.exe
bug02.pas: In function `program_Bug02':
bug02.pas:15: incompatible types in assignment

E:\DJGPP\GPC\BUG>gpc bug02.pas -o bug02.exe
bug02.pas: In function `program_Bug02':
bug02.pas:15: incompatible types in assignment
bug02.pas:16: incompatible types in assignment

E:\DJGPP\GPC\BUG>gpc bug02.pas -o bug02.exe

E:\DJGPP\GPC\BUG>bug02
OK
OK
5460
5456

O
OK
5460
5456


E:\DJGPP\GPC\BUG>


<-------------- END SCREENSHOT ------------------------>

What the @%^!? It compiled OK, but I forgot to use --automake! STRANGE! OK,
here comes the source:


BUG02.PAS:
----------

Program
    Bug02;
Uses
    Bug02_U;

{$X+}

Var
    ProcRec : TProcRec;
    S1,S2   : CString;
Begin
    ProcRec.Name1 := @NameFunc;
    ProcRec.Name2 := @NameFunc;

    S1 := ProcRec.Name1^;   { Line 15 }
    S2 := ProcRec.Name1^;   { Line 16 }

    WriteLn(ProcRec.Name1^);
    WriteLn(S1);
    WriteLn(Word(ProcRec.Name1)); { Testing Procedure Address }
    WriteLn(Word(S1));            { Testing CString Address   }
    WriteLn;

    WriteLn(ProcRec.Name2^);
    WriteLn(S2);
    WriteLn(Word(ProcRec.Name2));
    WriteLn(Word(S2));
    WriteLn;
End.



BUG02_U.PAS:
------------

Unit
    Bug02_U;

{$X+}

Interface

Type
    TProcRec = Record
        Name1 : ^Function : CString;
        Name2 : ^Function : CString;
    End;

Function NameFunc : CString;


Implementation

Function NameFunc : CString;
    Begin
        NameFunc := 'OK';
    End;

End.



<----------------------------------------------------->

This is one of those nightmare bugs because it shows up at random times.
Hang on, Ive just had an --IDEA--! Please wait while I compile once more...

DAMN - Its not unit related. Compiling the program below gave me the
following error messages. NOTE: It compiled OK the first time!?!?

<-------------- BEGIN SCREENSHOT ---------------------->

E:\DJGPP\GPC\BUG>gpc bug03.pas -o bug03.exe

E:\DJGPP\GPC\BUG>gpc bug03.pas -o bug03.exe
bug03.pas: In function `program_Bug02':
bug03.pas:24: incompatible types in assignment

E:\DJGPP\GPC\BUG>gpc bug03.pas -o bug03.exe
bug03.pas: In function `program_Bug02':
bug03.pas:24: incompatible types in assignment
bug03.pas:25: incompatible types in assignment

E:\DJGPP\GPC\BUG>gpc bug03.pas -o bug03.exe
bug03.pas: In function `program_Bug02':
bug03.pas:24: incompatible types in assignment
bug03.pas:25: incompatible types in assignment

E:\DJGPP\GPC\BUG>bug03
O
OK
1408960
5456

OK
OK
1408960
5456


E:\DJGPP\GPC\BUG>

<-------------- END SCREENSHOT ------------------------>


BUG03.PAS:
----------

Program
    Bug02;

{$X+}

Type
    TProcRec = Record
        Name1 : ^Function : CString;
        Name2 : ^Function : CString;
    End;

Function NameFunc : CString;
    Begin
        NameFunc := 'OK';
    End;

Var
    ProcRec : TProcRec;
    S1,S2   : CString;
Begin
    ProcRec.Name1 := @NameFunc;
    ProcRec.Name2 := @NameFunc;

    S1 := ProcRec.Name1^;  { Line 24 }
    S2 := ProcRec.Name1^;  { Line 25 }

    WriteLn(ProcRec.Name1^);
    WriteLn(S1);
    WriteLn(Word(ProcRec.Name1));
    WriteLn(Word(S1));
    WriteLn;

    WriteLn(ProcRec.Name2^);
    WriteLn(S2);
    WriteLn(Word(ProcRec.Name2));
    WriteLn(Word(S2));
    WriteLn;
End.


<--------------------------------------------------------------->

I hope I dont cause too much headache with this bug report :~( 

I know how bad it is hunting down bugs. I had to fix a last minute bug over
the weekend - The program was scheduled to be delivered to the client on
Monday (Today). Luckily it was a success! Now Ive got a week of holiday -
then I go back to UNI! Busy, busy, busy -- And Im only 18!! Whats to come of
the future!! AAARRGGHHH! :-)

Once again, Good Luck

 ________________________
|  _)        | |             e-mail: bernie@icenet.com.au
|___)ernhard |_|schirren             ptschirrenb@cc.curtin.edu.au
                             www:    www.geocities.com/CollegePark/Quad/8070/

Bernhard Tschirren (bernie@icenet.com.au)