eval {
                    local $SIG{ALRM} = sub { die "alarm\n" }; # NB: \n required
                    alarm $timeout;
                    $nread = sysread SOCKET, $buffer, $size;
                    alarm 0;
                };
                if ($@) {
                    die unless $@ eq "alarm\n";   # propagate unexpected errors
                    # timed out
                }
                else {
                    # didn't
                }