$fd->setsockopt(SOL_SOCKET, SO_LINGER, pack('l', 1));

##</code><code>##

$fd->setsockopt(SOL_SOCKET, SO_LINGER, pack('S', 1));

##</code><code>##

$fd->setsockopt(SOL_SOCKET, SO_LINGER, pack('ll', 1, 1));

##</code><code>##

$fd->setsockopt(SOL_SOCKET, SO_LINGER, pack('ss', 1, 1));