PHP: socket_get_option - Manual

SO_DEBUG Reports whether debugging information is being recorded. int SO_BROADCAST Reports whether transmission of broadcast messages is supported. int SO_REUSEADDR Reports whether local addresses can be reused. int SO_REUSEPORT Reports whether local ports can be reused. int SO_KEEPALIVE Reports whether connections are kept active with periodic transmission of messages. If the connected socket fails to respond to these messages, the connection is broken and processes writing to that socket are notified with a SIGPIPE signal. int SO_LINGER

Reports whether the socket lingers on socket_close() if data is present. By default, when the socket is closed, it attempts to send all unsent data. In the case of a connection-oriented socket, socket_close() will wait for its peer to acknowledge the data.

If l_onoff is non-zero and l_linger is zero, all the unsent data will be discarded and RST (reset) is sent to the peer in the case of a connection-oriented socket.

On the other hand, if l_onoff is non-zero and l_linger is non-zero, socket_close() will block until all the data is sent or the time specified in l_linger elapses. If the socket is non-blocking, socket_close() will fail and return an error.

array. The array will contain two keys: l_onoff and l_linger. SO_OOBINLINE Reports whether the socket leaves out-of-band data inline. int SO_SNDBUF Reports the size of the send buffer. int SO_RCVBUF Reports the size of the receive buffer. int SO_ERROR Reports information about error status and clears it. int (cannot be set by socket_set_option()) SO_TYPE Reports the socket type (e.g. SOCK_STREAM). int (cannot be set by socket_set_option()) SO_DONTROUTE Reports whether outgoing messages bypass the standard routing facilities. int SO_RCVLOWAT Reports the minimum number of bytes to process for socket input operations. int SO_RCVTIMEO Reports the timeout value for input operations. array. The array will contain two keys: sec which is the seconds part on the timeout value and usec which is the microsecond part of the timeout value. SO_SNDTIMEO Reports the timeout value specifying the amount of time that an output function blocks because flow control prevents data from being sent. array. The array will contain two keys: sec which is the seconds part on the timeout value and usec which is the microsecond part of the timeout value. SO_SNDLOWAT Reports the minimum number of bytes to process for socket output operations. int TCP_NODELAY Reports whether the Nagle TCP algorithm is disabled. int MCAST_JOIN_GROUP Joins a multicast group. array with keys "group", specifying a string with an IPv4 or IPv6 multicast address and "interface", specifying either an interface number (type int) or a string with the interface name, like "eth0". 0 can be specified to indicate the interface should be selected using routing rules. (can only be used in socket_set_option()) MCAST_LEAVE_GROUP Leaves a multicast group. array. See MCAST_JOIN_GROUP for more information. (can only be used in socket_set_option()) MCAST_BLOCK_SOURCE Blocks packets arriving from a specific source to a specific multicast group, which must have been previously joined. array with the same keys as MCAST_JOIN_GROUP, plus one extra key, source, which maps to a string specifying an IPv4 or IPv6 address of the source to be blocked. (can only be used in socket_set_option()) MCAST_UNBLOCK_SOURCE Unblocks (start receiving again) packets arriving from a specific source address to a specific multicast group, which must have been previously joined. array with the same format as MCAST_BLOCK_SOURCE. (can only be used in socket_set_option()) MCAST_JOIN_SOURCE_GROUP Receive packets destined to a specific multicast group whose source address matches a specific value. array with the same format as MCAST_BLOCK_SOURCE. (can only be used in socket_set_option()) MCAST_LEAVE_SOURCE_GROUP Stop receiving packets destined to a specific multicast group whose source address matches a specific value. array with the same format as MCAST_BLOCK_SOURCE. (can only be used in socket_set_option()) IP_MULTICAST_IF The outgoing interface for IPv4 multicast packets. Either int specifying the interface number or a string with an interface name, like eth0. The value 0 can be used to indicate the routing table is to used in the interface selection. The function socket_get_option() returns an interface index. Note that, unlike the C API, this option does NOT take an IP address. This eliminates the interface difference between IP_MULTICAST_IF and IPV6_MULTICAST_IF. IPV6_MULTICAST_IF The outgoing interface for IPv6 multicast packets. The same as IP_MULTICAST_IF. IP_MULTICAST_LOOP The multicast loopback policy for IPv4 packets enables or disables loopback of outgoing multicasts, which must have been previously joined. The effect differs, however, whether it applies on unixes or Windows, the former being on the receive path whereas the latter being on the send path. int (either 0 or 1). For socket_set_option() any value will be accepted and will be converted to a boolean following the usual PHP rules. IPV6_MULTICAST_LOOP Analogous to IP_MULTICAST_LOOP, but for IPv6. int. See IP_MULTICAST_LOOP. IP_MULTICAST_TTL The time-to-live of outgoing IPv4 multicast packets. This should be a value between 0 (don't leave the interface) and 255. The default value is 1 (only the local network is reached). int between 0 and 255. IPV6_MULTICAST_HOPS Analogous to IP_MULTICAST_TTL, but for IPv6 packets. The value -1 is also accepted, meaning the route default should be used. int between -1 and 255. SO_MARK Sets an identifier on the socket for packet filtering purpose on Linux. int SO_ACCEPTFILTER Adds an accept filter on the listened socket (FreeBSD/NetBSD). An accept filter kernel module needs to be loaded beforehand on FreeBSD (e.g. accf_http). string name of the filter (length 15 max). SO_USER_COOKIE Sets an identifier on the socket for packet filtering purpose on FreeBSD. int SO_RTABLE Sets an identifier on the socket for packet filtering purpose on OpenBSD. int SO_DONTTRUNC Retain unread data. int SO_WANTMORE Give a hint when more data is ready. int TCP_DEFER_ACCEPT Don't notify a listening socket until data is ready. int SO_INCOMING_CPU Gets/Sets the cpu affinity of a socket. int SO_MEMINFO Gets all the meminfo of a socket. int SO_BPF_EXTENSIONS Gets the supported BPF extensions by the kernel to attach to a socket. int SO_SETFIB Sets the route table (FIB) of a socket. (FreeBSD only) int SOL_FILTER Filters attributed to a socket. (Solaris/Illumos only) int TCP_KEEPCNT Sets the maximum number of keepalive probes TCP should send before dropping the connection. int TCP_KEEPIDLE Sets the time the connection needs to remain idle. int TCP_KEEPINTVL Sets the time between individual keepalive probes. int TCP_KEEPALIVE Sets the time the connection needs to remain idle. (macOS only) int TCP_NOTSENT_LOWAT Sets the limit number of unsent data in write queue by the socket stream. (Linux only) int