On 16.07.2011 22:37, Hans-Peter Diettrich wrote:
There seems to exist an issue with (output) redirection, when I try to run an external program from code. What I want to achieve is this:In a Win32 console I can run >diff -r dir1 dir2 > diff.txt When I use e.g. Exec('diff', args), diff complains about an excess argument, it works when "> diff.txt" is removed. With other functions I had less luck (ExecuteProcess, CreateProcess...), no output at all. Now I assume that output redirection is a shell feature, not available in direct invocation of an external program. Right?
In addition to the solution given by Andrew (namely using TProcess), I'd like to confirm that input/output redirection using ">", "<", "|", etc. is indeed a feature of the shell (be it DOS shell, NT command line or bash). To use input/output redirection yourself in a program you need to point the Stdin, Stdout and/or Stderr handles of the called program to the source or sink you desire. For Windows that means passing handles for StdIn, StdOut and StdErr to CreateProcess. I don't know the procedure on Linux, but there the same basic concept applies. All this is encapsulated by TProcess.
Regards, Sven _______________________________________________ fpc-devel maillist - fpc-devel@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-devel
