Mega Code Archive
Assert
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You can create your own symbol (called DEBUG, say) and have
{$ifdef DEBUG} {$D+} {$else} {$D-} {$endif}
and set both $D and your conditional simultaneously. There's no really clean
way to do Assert in Delphi; the one I prefer is
const
debug = {$ifdef DEBUG} true {$else} false {$endif};
procedure Assert(condition:boolean);
begin
if not condition then {give some error message} ;
end;
Now, to put a call to Assert into your program only while debugging, use
if debug then Assert(X>1);
The call to Assert will be stripped out if debug is false; if you make no
references to Assert that don't get stripped, then the whole routine will be
stripped out of the executable.
>My next question is: is there any trick how to generate the line number
>like in MFC ? Probably not, because of unavailability of macro, am I right ?
No, there's no way I know of. You can call Runerror() to generate a run-time
error and print the address; you could write a program to search through a
..map file to find that address, or just ask the IDE to do the search for you
(with Find Error).
Duncan Murdoch
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From: dmurdoch@mast.queensu.ca (Duncan Murdoch)
Subject: Re: ASSERT in Delphi/Pascal
Date: Sun, 14 May 1995 12:40:26 GMT
I guess I'll have to change my recommendation: Don't use "if debug then
Assert...", use "{$ifdef debug} Assert... {$endif}". Sorry for the bad advice.
Duncan Murdoch
-------------------------------------------------------------------------------
From: ag623@FreeNet.Carleton.CA (Lester Kovac)
Subject: Re: ASSERT in Delphi/Pascal
Date: Wed, 17 May 1995 04:03:47 GMT
There is nothing to be sorry for. I'm thankfull to everybody who
contributed to this thread. I would just suggest the best would be the
condition according to Sean Palmer's advice:
{$IFOPT D+} Assert(condition, "Pointer not initialized"); {$ENDIF}
Thus we do not need to maintain DEBUG conditional define.
--
Lester Kovac
Nepean, Ontario, Canada
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From: vandewb@wkuvx1.wku.edu (Jay Cole)
Subject: Definitive Assert in Delphi
Date: 18 Jun 95 10:07:22 CDT
Well, here it is...
The definitive Assert. Better than the line numbers supplied w/ the
C/C++ Assert, this assert gives you the "find|error" logical address
of the calling module that called assert. It returns the ssss:oooo
seg offset pair so you can find where the assert was called. Again,
you can use the ifopt D+ if you wish but I prefer a define _NDEBUG
instead. Hopefully this is the end-all assert. Use freely, just drop
me an e-mail at vandewb@wku.wkuvx1.edu if you find it useful.
Here it is...Jay Cole
{ Call if you need to verify implied conditions }
procedure Assert(assertedCond : boolean; const msgStr : string);
implementation
{$ifdef WINDOWS}
uses WinProcs, SysUtils, WinTypes;
{$else}
uses sysUtils;
{$endif}
{ Error when the assumption made is not correct. }
procedure Assert(assertedCond : boolean; const msgStr : string);
var
msgOut : array[0..300] of char;
hexStr : array[0..30] of char;
progSeg, progOfs : word;
tmpStr : string;
begin
{ Get the logical segment used by the Find|Error menu option of
delphi }
asm
mov ax, [bp+04] { Load physical segm of the calling
proc on call stack }
mov es, ax
mov ax, word ptr es:0 { Logical segm stored in 0th position
of physical seg }
mov progSeg, ax { Logical, not physical segm used in
Find|Error menu item }
mov ax, [bp+02]
mov progOfs, ax { Physical ofs is used by find|error,
no translation needed }
end;
{$ifndef _NDEBUG} { Are we allowed to assert? }
if (not assertedCond) then begin
{ construct msg\nat location ssss:oooo using the logical address
}
StrPCopy(msgOut, msgStr);
tmpStr := chr(10)+'at location
'+IntToHex(progSeg,4)+':'+IntToHex(progOfs,4);
StrPCopy(hexStr, tmpStr);
StrCat(msgOut, hexStr);
{$ifdef WINDOWS}
MessageBox(0, msgOut, 'Assert Failed',
MB_ICONSTOP+MB_SYSTEMMODAL+MB_OK);
{$else}
WriteLn('Assert Failed', msgOut);
{$endif}
{ Now, terminate the program because of assertion problem }
halt;
end;
{$endif}
end;
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