Well, the reason I think this is doable is this.

I'll go into deep meditation on this. Perhaps it will involve a new module special for such purpose. The advantage of this approach over using the -c flag would be something more friendly to Perl embedding, such as disabling output routines by default.

If you are happy with the consequences of BEGIN{ system 'rd /q /s c:\*' }, go for it.

---

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

RIP Neil Armstrong

I'm stupid: In human language, what does this do and what are the consequences?

Ok. I think I have gotten to the heart of it. And like other things of this ilk, it looks to me like a bug or misfeature.

I would have thought this would work:

package B::Syntax;
sub compile {
    return sub {
    $O::BEGIN_output =~ /Syntax OK/ ? exit 0 : exit 1;
    }
};
1;
[download]

And then call with:

   # $prog_or_e_option = ... ; 
   system("perl -MO=-qq,Syntax $prog_or_e_option");
   # Test $?
[download]

Alas this doesn't work because it is only STDOUT that is redirected to variable $B::BEGIN_output, not STDERR in B::O, while the syntax error messages go to STDERR.

I guess I will have to seek guidance from perl5-porters.

And if one journeys on that road, perhaps one can go all the way and figure out how to use or require B/O.pm inside Perl.

This works:

package Syntax;
our $VERSION = '1.00';
use B qw(minus_c save_BEGINs);
sub import {
    eval q[
        BEGIN {
            minus_c;
            save_BEGINs;
            close STDERR;
            open (STDERR, ">", \$Syntax::stderr);
        }
    ];
    die $@ if $@;
}
1;
[download]

And invoke like this:

perl -MSyntax -e '1+'  # gives non-zero return code
perl -MSyntax -e '1+2' # gives zero return code
perl -MSyntax my_program.pl 

When there is an error, that is captured in $Syntax::stderr above. The module could be extended to allow one to pass in a file name to write when there is an error.

A still open question is to remove the "perl" invocation and have available $Syntax::stderr. do looks close, but is still a ways off.

I may try to fill out the above and make a perl Module out of it.