[fpc-pascal] Linux program sometimes crashes with "EProcess : Failed to create pipes"

[Burkhard Carstens]

Am Donnerstag, 10. September 2009 11:01 schrieb T. Guilleminot:
> Hi,
>
> Have a Linux program that recently started to crash several times
> with such message :
> An unhandled exception occurred at $080A4CB9 :
> EProcess : Failed to create pipes
>   $080A4CB9
>   $080A4D3D
>   $080526E0
>   $08057C11
>   $08058809
>   $B7B082B6
>   $B7B07B88
>   $B7B0B0EB
>   $B7B0B5BA
>   $B7CF57D9
>   $0805AABD
>
> This seems only occurs after a long running period of time.
> Considering error message and as it runs very often some OS processes
> I suspect TProcess. I use such procedure :
>
>   Procedure Run_Command(Wait : boolean; TheCommand : ansistring);
> cdecl; export;
>   var
>     AProcess: TProcess;
>   Begin
>     AProcess := TProcess.Create(nil);
>     AProcess.CommandLine := TheCommand;
>     if Wait = true then AProcess.Options := AProcess.Options +
> [poWaitOnExit];
>     AProcess.Execute;
>     AProcess.Free;
>   end;
>
> I think I may hit some OS limits or I overload system.
> Does anyone know how to diagnose this further (why it fails...)
> and/or to fix this ?
Using this procedure with wait=false leaves you a zombie process. I.e. 
even, if "TehCommand" finished, the process isn't closed unless you 
call fpWaitPID (or better WaitOnExit) on it's pid.
Not sure, but probably the zombie still holds the pipes and therefore 
you run out of handles and some point.

see also: http://mantis.freepascal.org/view.php?id=11797 

regards
 Burkhard