I wrote a similar construct for an updated version of Proc::Daemon - The updated code has not been released under the Proc::Daemon namespace as yet however as I am waiting to hear back from Earl Hood, the maintainer of Proc::Daemon, with his comments on the proposed code changes.

The updated Fork subroutine code follows:

sub Fork {
    my $pid;
    my $retry = 0;

    #   The following loop structure is responsible for performing a f
+ork safely - 
    #   If the core fork function returns a valid process identificati
+on value, 
    #   this is returned and this subroutine is exited.  If however, a
+n error 
    #   occurs, an attempt is made to retry the fork, if the error mes
+sage is the 
    #   result of no additional processes.  This is attempted $RETRY t
+imes after 
    #   sleeping for $SLEEP seconds before execution is abandoned.

    FORK: {
        if ( defined( $pid = fork ) ) {
            return $pid;
        } elsif ( $! =~ /No more process/i ) {
            if ( ++$retry > ( $RETRY || 3 ) ) {
                croak( __PACKAGE__, '::Fork - Cannot fork process, ret
+ry count exceeded - ', $! );
            }

            sleep ( $SLEEP || 5 );
            redo FORK;
        } else {
            croak( __PACKAGE__, '::Fork - Cannot fork process - ', $! 
+);
        }
    }
}
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perl -le 'print+unpack("N",pack("B32","00000000000000000000001000101111"))'