I'm looking for an idiom or pattern.

I have a subroutine. I'd like to call it and handle problems it might encounter. I could implement so that I can call it this way: 

($success, $err_msg) = my_sub();
unless ($success) {
  # handle error condition using $err_msg
}

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But I would much rather set things up so I can use the more concise: 
unless ( my_sub() ) {
   # handle error condition
}

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or... 
unless ( $result = my_sub() ) {
   # handle error condition
}

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Can I co-opt a global special error var to set on error in my sub? I've checked on a couple possibilities but haven't found anything promising. E.g. you can assign a number to $! but apparently only to cause it to point to an existing system error description if $! is then used in string context.

My religion forbids me to use globals of my own creation, so I'd like to avoid that if I can. ;-)

TIA, David

In reply to Idomatic Handling of Subroutine Error by dvergin

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