Here's another gotcha that bit me just yesterday, that, in retrospect seems so obvious:

   sub main_code
   {
       while(1) {
          eval{ fork_and_do_stuff() };
          print STDERR "error, but we go on anyways\n";
       }
   }

   sub fork_and_do_stuff
   {
       my $pid = fork
       if( $pid == 0 ) { ## simplified...
           do_stuff();
           exit 1;
        }
   }
[download]

So what happens if you die() within do_stuff() ? The control would actually go to the eval block enclosing the fork_and_do_stuff() call! I've inadvertantly a child process that would execute the parent code.

That obviously sucks.

The solution is to put yet another eval block in the child code:

   sub fork_and_do_stuff
   {
       my $pid = fork
       if( $pid == 0 ) { 
           eval{ do_stuff() };
           exit 1;
        }
   }
[download]

After this, I'm definitely going to be in the habit of putting all forked code in some sort of eval block to make sure that I can safely wrap the forking code in another eval block...