Re^3: Question regarding handling exceptions in subroutine

[space_monk]

The obvious answer is to remove the croak (or perhaps change it to a carp/warn).

You can run a command in backticks to trap both the output and the status code it returns. So you should be able to do something like:

my $response=`useradd fred ....`;
#check the status code (0 = success)
if ($? >>8) {
  # we could not add the user
}

[karlgoethebier]

Shouldn't it be something like this?

Update:

OK, eval...

my $result;
eval {
    $result = qx($command);
};

if ( $? >> 8 != 0 ) {
    if ($@) {
        die $@;
    }
    else {
        die qq(Something really weird happened!);
    }
}
# do stuff with $result...

Regards, Karl

[space_monk]

Thanks, you're right about the other issues, I was simply in a hurry to outline a way forward_{at least that's the excuse I'm using :-)}

Question: Why 'eval' this instead of just running this in backticks? I understand the command can fail, but in those cases it simply returns an error code.

[karlgoethebier]

"Why 'eval' this..."

Good question. Because:

1. I'm paranoid
2. I didn't think
3. I was in a hurry

Perhaps all items match ;-)

My posts aren't correct: it would only make (some) sense to eval if there is a die in the block that sets $@ (perhaps something wrong with $command, like a non-existing file etc). But this could be also trapped before with a file test operator...a.s.o

I just wanted to say that you forgot to right shift, as you already noticed. That would have been enough. Sorry :-(

Update:

To tell the truth: from time to time i need to take a look again at Perl documentation about this issues. I think it can be tricky - depending on the situation. And even if it isn't really tricky, i get a little confused about it from time to time...

Best regards, Karl

[karlgoethebier]

Shouldn't it be:

my $result = qx($command);

if ( $? >> 8 != 0 ) {
    if ($@) {
        die $@;
    }
    else {
        die qq(Something really weird happened!);
    }
}

Regards, Karl