[fpc-pascal] Question about TProcess

[Vincent Snijders]

Darius Blaszijk schreef:
> The following piece of code is giving me headaches. When I add the 
> option poUsePipes, the application starts and does not seem to do 
> anything else anymore. It just opens a commandline terminal and that is 
> that. When I leave the option out the application actually starts "make" 
> and then crashes because AProcess.Output is nil.
> What did I forget? I'm working on WinXP. On Linux btw the code works.
> 
> Darius
> 
> procedure ExecuteApp(CmdLine: string);
> var
>  AProcess: TProcess;
>  AStringList: TStringList;
> begin
>  AProcess := TProcess.Create(nil);
>  AStringList := TStringList.Create;
>  AProcess.CommandLine := CmdLine;
>  AProcess.Options := AProcess.Options + [poWaitOnExit, poUsePipes];
>  AProcess.Execute;
>  AStringList.LoadFromStream(AProcess.Output);
>  AStringList.SaveToFile('output.txt');
>  AStringList.Free;
>  AProcess.Free;
> end;
> 
> begin
>  ExecuteApp('make');
> end.

Maybe the output buffer is full and the application is waiting for you 
to read from the pipe. See the reading large output program at
http://wiki.lazarus.freepascal.org/Executing_External_Programs#Reading_large_output

Vincent