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Re: Idomatic Handling of Subroutine Error

by btrott (Parson)
on Sep 18, 2001 at 22:58 UTC ( #113177=note: print w/replies, xml ) Need Help??

in reply to Idomatic Handling of Subroutine Error

Other posters have mentioned exceptions; that's a good way to go.

Another option is more similar to the sample code you posted. If you are willing to call your subroutines as object or class methods, you can have your methods return undef on error, and set either an instance variable or a class variable, which the calling code can then access using some other method you set up, like 'errstr'. For example, here is some error-handling code I use:

use vars qw( $ERROR ); sub new { bless {}, shift } sub error { my $msg = $_[1]; $msg .= "\n" unless $msg =~ /\n$/; if (ref($_[0])) { $_[0]->{_errstr} = $msg; } else { $ERROR = $msg; } return; } sub errstr { ref($_[0]) ? $_[0]->{_errstr} : $ERROR }
In your methods you can now do:
return $obj->error("Got an error") unless $foo; ## OR return $class->error("Got an error") unless $foo;
And in the calling code you can do:
$obj->foo or die $obj->errstr; ## OR My::Class->foo or die My::Class->errstr;

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