[GRASS-dev] another not quiet GRASS command

[Paul Kelly]

On Mon, 3 Sep 2007, Michael Barton wrote:

> The problem in this and other cases is that the warning is sent to stderr
> when the command operates and exits properly. Error messages are sent to
> stderr when the command does not operate properly and/or exits with an
> error. There is no easy way (maybe no way in many cases) for a script to
> tell the difference.

I think Tcl's deficiencies are confusing you. Tcl cannot tell the 
difference and this is IMHO a major bug in Tcl. But it is a single 
exception. Operating systems and probably almost all other scripting 
languages use the exit code of the program: a zero exit code indicates it 
exited successfully; a non-zero exit code indicates it exited with an 
error.

In any case Maris seems to have found a workaround to Tcl's deficiency: 
check the global variable errorcode after running an external command. I'm 
waiting to see if anybody comes up with a problem with this approach.