#!/usr/bin/perl -w
use strict;

# Lots of nice code here...

open RFIFO, "< $ENV{HOME}/.fifopipe" 
  or die "Cannot open read pipe: $!\n";

open WFIFO, "> $ENV{HOME}/.fifopipe" 
  or die "Cannot open write pipe: $!\n";

if (fork()) { # Parent

  close WFIFO;

  # Your parent code, which can now safely block on
  # <RFIFO>

}
else { # Child

  close RFIFO;

  # Your child code, which can take its time to write()
  # to the pipe.

  exit 0;
}