From maintainers-request at octave dot org Thu Sep 22 21:06:17 2005
Subject: Re: popen2 example gives no output
From: Bill Denney <denney at seas dot upenn dot edu>
To: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
cc: octave maintainers mailing list <maintainers at octave dot org>,         Brian Blais <bblais@bryant.edu>
Date: Thu, 22 Sep 2005 22:02:37 -0400 (EDT)

On Thu, 22 Sep 2005, John W. Eaton wrote:

> The simple solution to associating the list of names and error codes
> would be to have just the EXXX values that are defined by POSIX
> (http://www.opengroup.org/onlinepubs/009695399/basedefs/errno.h.html)
> but it seems that it would be better to have whatever symbolic names
> are available on a given system.  To implement this, we would need to
> do some grepping through errno.h (and any files it includes).  That
> seems ugly, and duplicates what Perl (at least) already does.  So it
> seems to me that it would be cleaner to use Perl to generate the list
> for Octave, when Octave is built.  That would introduce a build
> dependency on Perl.  Is that a problem?  Perhaps we could fall back on
> the list of names from POSIX if Perl is not available?  Otherwise, we
> would have to duplicate a lot of fairly tricky code, and that seems
> even less desirable to me.
>
> Can some Perl guru on the list tell me how to use the Errno module in
> Perl to generate a list of all the symbolic error codes, as strings?

I think that this is what you're asking for:

=== Begin Script
#!/usr/bin/perl

foreach my $key (keys(%!)) {
     print "$key\n";
}
=== End Script

I don't know all the C that you're wanting to put in there, but if it's 
just what you wrote below, this script will do it (just for the static 
errno_name_value_struct errno_codes part):

=== Begin Script
#!/usr/bin/perl

foreach my $key (keys(%!)) {
     print "  { \"$key\", $key },\n";
}
=== End Script

Also, I thought that Perl was already a build dependency for the 
lsode_options (and *_options) code, so adding this shouldn't really be an 
issue.

Bill

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