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(PHP 4 >= 4.3.0, PHP 5)

socket_get_optionGets socket options for the socket


mixed socket_get_option ( resource $socket , int $level , int $optname )

The socket_get_option() function retrieves the value for the option specified by the optname parameter for the specified socket.



A valid socket resource created with socket_create() or socket_accept().


The level parameter specifies the protocol level at which the option resides. For example, to retrieve options at the socket level, a level parameter of SOL_SOCKET would be used. Other levels, such as TCP, can be used by specifying the protocol number of that level. Protocol numbers can be found by using the getprotobyname() function.

Available Socket Options
Option Description Type
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_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

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

Return Values

Returns the value of the given option, or FALSE on errors.


Example #1 socket_set_option() example


$linger = array('l_linger' => 1'l_onoff' => 1);



Version Description
4.3.0 The name of this function was changed. It used to be called socket_getopt().

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User Contributed Notes 3 notes

Chad Lavoie
6 years ago
If using Unix Sockets, and you want to use SO_PEERCRED, you can use the number 17 for the optname (and SOL_SOCKET for the level).  The PID of the connecting process will be returned.
recycling dot sp dot am at gmail dot com
6 years ago
Just 2 notes here:
- On UNIX, If SO_DEBUG is set, the php program needs an effective user id of 0.
-  activating SO_OOBINLINE on a socket is equivalent to passing MSG_OOB flag to each recieving functions used with that socket (eg: socket_recv, socket_recvfrom).
prennings at gmail dot com
2 years ago
I was playing around with this option to use multiply socket connections with same hostname and same port (IRC). However the socket function needed for this is SO_REUSEPORT.

Though the majority of linux distro's does not have that yet officially implented in there distro's.

However for debian there is an patch that can be installed to get it working:

it has some work but I got it working after a while (Noobie in debian) maybe some other people are facing the same problem as I was.
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