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Re^4: Friendly error trapping

by bradcathey (Prior)
on Sep 13, 2005 at 12:00 UTC ( [id://491556]=note: print w/replies, xml ) Need Help??


in reply to Re^3: Friendly error trapping
in thread Friendly error trapping

Points well taken graff. I'm embarrassed to say, I have not used eval to trap errors. How about a little lesson here... if I were to trap the error in the OP would it look something like this?

eval { uploader($dir, $name) };
print "There was a problem uploading your file: $@" if ($@);

sub uploader {
   my ($upload_dir, $filename) = @_;
   ...
   open UPLOADFILE, ">$upload_dir/$filename" or die;
}

[download]

So, I can go ahead and die and the eval will trap and return the error without fatally terminating the script? Thanks!


—Brad
"The important work of moving the world forward does not wait to be done by perfect men." George Eliot

Replies are listed 'Best First'.
Re^5: Friendly error trapping
by graff (Chancellor) on Sep 13, 2005 at 19:06 UTC
    Right -- just make sure you include some appropriate message with the "die" call, because that is what $@ will be set to; e.g.: 
    eval { uploader( $dir, $name ) };
print "There was a problem uploading your file: $@" if ( $@ );

sub uploader {
    my ($upload_dir, $filename) = @_;
    ...
    open UPLOADFILE, ">$upload_dir/$filename"
        or die "Open for output failed on $upload_dir/$filename: $!";
    ...
    print UPLOADFILE ... or die "Output failed on $upload_dir/$filenam
+e: $!";
    ...
    close UPLOADFILE or die "Unable to close $upload_dir/$filename: $!
+";
    ...
}

    [download]
    If none of the die statements is invoked, $@ will come back undef and everything is fine; otherwise, $@ will be set to whichever message was passed to the die call, the thing uploader() was trying to do will have failed in some way, and the caller will keep running.
[reply]
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