You while loop will terminate when you've reached EOF on the pipe or there was an error. In the first case $bytes will be 0 and the second it'll be undef. To get the exit status of the child, you don't need to install a SIGCHLD handler. Just waitpid for the child process to terminate and check $?. So, here's one way to get the status w/o using SIGCHLD:

use POSIX ":sys_wait_h";
my $pid = open(INPIPE, "$reader_prog $options |") or die "open failed:
+ $!";
while ($bytes = read(INPIPE, $bugger, 32768)) {
    print $buffer;
}
if (!defined($bytes)) {
    print "read error: $!\n";
}
my $kid = waitpid($pid, WNOHANG);
unless ($kid == $pid) {
   print "child process $pid is still running\n";
   print "trying close\n";
   close(INPIPE);
   print "child status is $?\n";
} else {
   print "child process $pid reaped, status is: $?\n";
}
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Notes:

• If the child terminates, the pipe will be closed, and eventually you'll get EOF when trying to read from it.
• Be aware that the child can close the pipe but continue to run.
• When using read, getting a read length of 0 means that the pipe was closed. read will wait for data to become present if none is available at the time (i.e. it will block).
• To check if data is available to be read from the pipe, use select.
• Using close will close the parent's end of the pipe and wait for the child to terminate. In this case, the parent executing close will cause the child to get a SIGPIPE error when it tries to write to the pipe, and this usually will cause the child to terminate.