You're almost there. 
# MAIN
unless ($result = my_sub() ) {
    # Now you use $result if it's not 0
}

# WRAPPER function
sub my_sub {
   eval { _my_sub(@_) };
   if ($@) {
      return $@;
   } else {
      return '';
   }
}

# Actual worker...
sub _my_sub {
# Do your stuff here. If something fails, do a die with a useful error
+ message. Otherwise, return 0.

    # For example ...
    die "Bad data passed in.\n";
}

[download]
You actually do a die which doesn't end your script - it gets trapped by the eval and the string you passed die will be put in $@.

Now, I personally dislike this type of error-handling because 0 is FALSE and non-zero is TRUE. Thus, you have to flip your thinking the way the C libs force you to and say you're calling the function and hope it "fails" for success. (Sorta like a drug screening ...)

Instead, I would something similar. Instead of passing back '' for success, I'd pass back undef instead. 

# MAIN
if (defined ($error = my_sub()) ) {
    # Now you use $error if it's defined
}

# WRAPPER function
sub my_sub {
   eval { _my_sub(@_) };
   if ($@) {
      return $@;
   } else {
      return undef;
   }
}

# Actual worker...
sub _my_sub {
# Do your stuff here. If something fails, do a die with a useful error
+ message. Otherwise, return 0.

    # For example ...
    die "Bad data passed in.\n";
}

[download]
It seems like a semantic difference, but now your code use TRUE and FALSE the way they intuitively used, to indicate success and failure.

------
We are the carpenters and bricklayers of the Information Age.

Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.

In reply to Re: Re: Re: Idomatic Handling of Subroutine Error by dragonchild
in thread Idomatic Handling of Subroutine Error by dvergin

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.