[GRASS5] G_done_msg(), stderr, and fileno()

[Paul Kelly]

Hello Hamish
On Tue, 25 Oct 2005, Hamish wrote:

> Hi,
>
> G_done_msg() does some figuring on where to send the output:
>        if (isatty(1))
>                out = stdout;
>        else if (isatty(2))
>                out = stderr;
>
> for one thing, shouldn't that use fileno(stdout) instead of "1", and
> for another shouldn't it try to send to stderr first? always?

I think it should. Shouldn't even bother checking.

> G_message(), G_warning(), and G_fatal_error() all send exclusively to
> stderr, with the bell getting a isatty(fileno(stderr)) test.
>
>
> I've written a script which calls a module which uses G_done_msg().
> I'd like to pipe the stdout to a file, but currently the output of
> G_done_msg() is polluting matters.

Yes exactly. We had a discussion a while ago about r.proj printing a 
message to say when it was finished or something and the suggestion was to 
use G_done_msg(...) instead of fprintf(stderr, ...). I looked at the 
source of G_done_msg() and thought that would be a bad idea so didn't 
change anything. Meant to bring it up on the list but didn't get round to 
it.

There must be a reason for the current logic in G_done_msg() though.

but in general, I feel the "output to stderr to stdout?" issue has been quite 
confused in GRASS for a long time until we decided that anything that was 
part of the results/analysis output of the module should go to stdout, 
while informative user messages should go to stderr.

So probably most of what's in G_done_msg() should be stripped out and 
simplified, IMHO.

Paul