[fpc-pascal] Windows unit and SyncObjs unit clash

Michael Van Canneyt michael at freepascal.org
Wed Mar 26 11:45:08 CET 2008



On Wed, 26 Mar 2008, Graeme Geldenhuys wrote:

> Hi,
> 
> I've noticed this ages ago and found a work-around, but never reported
> it. I hit the same error again today and thought this time I would
> mention it.
> 
> In tiOPF we have some IFDEF's for the 'Windows' unit. Some units also
> use the 'SyncObjs' unit for critical section handling. If 'SyncObjs'
> unit appears before the 'Windows' unit, our code fails to compile with
> a error referring to the TCriticalSection class.
> 
> Does anybody know about this?  Is there any permanent fix to that FPC
> doesn't depend on specific order in uses clause?

Yes, use fully qualified names.

windows.tcriticalsection.
syncobjs.tcriticalsection.

For lower level stuff, you should use TRTLCriticalSection, never TCriticalSection.

It has the advantage of being portable.

I'm surprised you actually use the windows unit. That is Evil(tm).

Michael.

> 
> I'm now using FPC 2.2.0, but this issue has been around since 2.0.2.
> 
> 
> ------------[ copy ]------------------
> C:\Programming\tiOPF2\Source\Core\tiUtils.pas(3491,13) Error: Unknown
> record field identifier "ENTER"
> 
> C:\Programming\tiOPF2\Source\Core\tiUtils.pas(3491,18) Error: Illegal expression
> 
> C:\Programming\tiOPF2\Source\Core\tiUtils.pas(3497,15) Error: Unknown
> record field identifier "LEAVE"
> 
> C:\Programming\tiOPF2\Source\Core\tiUtils.pas(3497,20) Error: Illegal expression
> 
> C:\Programming\tiOPF2\Source\Core\tiUtils.pas(3503,13) Error: Unknown
> record field identifier "ENTER"
> 
> C:\Programming\tiOPF2\Source\Core\tiUtils.pas(3503,18) Error: Illegal expression
> 
> C:\Programming\tiOPF2\Source\Core\tiUtils.pas(3509,15) Error: Unknown
> record field identifier "LEAVE"
> 
> C:\Programming\tiOPF2\Source\Core\tiUtils.pas(3509,20) Error: Illegal expression
> 
> C:\Programming\tiOPF2\Source\Core\tiUtils.pas(3526,32) Error: Unknown
> record field identifier "CREATE"
> 
> C:\Programming\tiOPF2\Source\Core\tiUtils.pas(3532,13) Error: Unknown
> record field identifier "FREE"
> 
> C:\Programming\tiOPF2\Source\Core\tiUtils.pas(3532,17) Error: Illegal expression
> 
> C:\Programming\tiOPF2\Source\Core\tiUtils.pas(3544,13) Error: Unknown
> record field identifier "ENTER"
> 
> C:\Programming\tiOPF2\Source\Core\tiUtils.pas(3544,18) Error: Illegal expression
> 
> C:\Programming\tiOPF2\Source\Core\tiUtils.pas(3548,15) Error: Unknown
> record field identifier "LEAVE"
> 
> C:\Programming\tiOPF2\Source\Core\tiUtils.pas(3548,20) Error: Illegal expression
> 
> C:\Programming\tiOPF2\Source\Core\tiUtils.pas(3560,13) Error: Unknown
> record field identifier "ENTER"
> 
> C:\Programming\tiOPF2\Source\Core\tiUtils.pas(3560,18) Error: Illegal expression
> 
> C:\Programming\tiOPF2\Source\Core\tiUtils.pas(3564,15) Error: Unknown
> record field identifier "LEAVE"
> 
> C:\Programming\tiOPF2\Source\Core\tiUtils.pas(3564,20) Error: Illegal expression
> 
> C:\Programming\tiOPF2\Source\Core\tiUtils.pas(3569) Fatal: There were
> 19 errors compiling module, stopping
> 
> ------------[ end ]-------------------
> 
> 
> And here is an example of where the cursor lands to show the error...
> 
> 
> function TtiMultiReadExclusiveWriteSynchronizer.LockForRead: boolean;
> 
> begin
> 
>   FCritSect.Enter;          // <<<<<<<<<  Cursor showing error
> 
>   try
> 
>     result:= CanLockForRead;
> 
>     if Result then
> 
>       Inc(FReadCount);
> 
>   finally
> 
>     FCritSect.Leave;
> 
>   end;
> 
> end;
> 
> 
> 
> 
> Regards,
>   - Graeme -
> 
> 
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