Exception handling - try Catch Method

[Anonymous Monk]

Hi,
I would like to open a file and if can not open, need to throw a message using Exception handling method(try-catch method).
How can i do that? I have written like this in normal method, how can i convert it try-catch method?

open (FH, "directory/myfile") || die "Can Not open the file";
@array = <FH>;
close(FH);

Can anyone post a solution here
Regards,
San

[Zaxo]

use Errno;
OPEN: eval {
    open FH, '<', 'directory/myfile'
        or die $!;
};
if ($@) {
    {
        $@ == EACCES and die $@;
        $@ == ENFILE and sleep(1), goto OPEN;
        warn $@;
    }
}

There are interesting definitions of try and catch to be seen around the monastery, but they all boil down to the construction I show.

[csuhockey3]

Have a look at try/catch (mirror) by pemungkah. Also read this article about Exception Handling in Perl.

csuhockey3

[tachyon]

Don't use that syntax until you have read Re: Re2: Learning how to use the Error module by example. Once you have read that you may well decide not to use it due to the inherent issues.

[Rakeswell]

Try this:

eval {open (FH, "directory/myfile") || die "Can Not open the file ($!)
+";};
if ($@){
      # handle your exception
      # maybe check contents of $@ to decide what to do
}

@array = <FH>;
close(FH);

[ybiC]

/me asks ignorantly...

I've seen try-catch stuff in my Java^(TM) dabblings, but it seems awkwARd and saskwAAtch.   Why, pray tell, might one *choose* to do it this way?

[adrianh]

See Best Practices for Exception Handling for some reasons.

[reneeb]

To use the try-catch-method you can use the Error-module: http://search.cpan.org/~uarun/Error-0.15/Error.pm

[dragonchild]

Read Re: Re2: Learning how to use the Error module by example before recommending Error.

[Matts]

Along with the suggestions here, don't forget to take a look at the Fatal module (run "perldoc Fatal" on the command line) to see how to have open() automatically throw an exception when it fails to open the file. This automates what I consider most of the hard work of exceptions in perl (i.e. actually remembering to throw them!), and also includes useful error text in the exception.