#! /usr/bin/perl -wT
use POSIX();
use strict;
require 5.008;

sub zap {
        $SIG{CHLD} = \&zap;  # loathe sysV, dream of real POSIX
        while (my $pid = waitpid(-1, POSIX::WNOHANG())) {
                last unless $pid>0;
                if ($? != 256) {
                        die("Caught a $?");
                }
        }
}

$SIG{CHLD} = \&zap;

my ($pid);
while (1) {
        FORK: foreach (1..4) {
                if ($pid = fork) {
                } elsif (defined $pid) {
                        sleep 1;
                        exit 1;
                } elsif ($! =~ /No more process/) {
                        sleep 5;
                        redo FORK;
                } else {
                        die("Can't fork");
                }
        }
}
__DATA__
perl -V gives
Summary of my perl5 (revision 5.0 version 8 subversion 0) configuration:
  Platform:
    osname=solaris, osvers=2.8, archname=sun4-solaris-thread-multi
    uname='sunos hostname 5.8 generic_108528-15 sun4u sparc sunw,sun-blade-100 '
    config_args=''
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=define use5005threads=undef useithreads=define usemultiplicity=define
    useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
    use64bitint=undef use64bitall=undef uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-D_REENTRANT -fno-strict-aliasing -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
    optimize='-O',
    cppflags='-D_REENTRANT -fno-strict-aliasing'
    ccversion='', gccversion='3.2.2', gccosandvers='solaris2.8'
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=4321
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -L/usr/local/lib '
    libpth=/usr/local/lib /usr/lib /usr/ccs/lib
    libs=-lsocket -lnsl -ldl -lm -lrt -lpthread -lc
    perllibs=-lsocket -lnsl -ldl -lm -lrt -lpthread -lc
    libc=/lib/libc.so, so=so, useshrplib=false, libperl=libperl.a
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags=' '
    cccdlflags=' ', lddlflags='-G -L/usr/local/lib'