socket_recvfrom
(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)
socket_recvfrom — Receives data from a socket whether or not it is connection-oriented
Description
Socket
$socket
,string
&$data
,int
$length
,int
$flags
,string
&$address
,int
&$port
= null
): int|false
The socket_recvfrom() function receives
length
bytes of data in data
from
address
on port port
(if the
socket is not of type AF_UNIX
) using
socket
. socket_recvfrom() can be
used to gather data from both connected and unconnected sockets.
Additionally, one or more flags can be specified to modify the behaviour of
the function.
The address
and port
must be
passed by reference. If the socket is not connection-oriented,
address
will be set to the internet protocol address of
the remote host or the path to the UNIX socket. If the socket is
connection-oriented, address
is null
. Additionally,
the port
will contain the port of the remote host in
the case of an unconnected AF_INET
or
AF_INET6
socket.
Note: This function is binary-safe.
Parameters
-
socket
-
The
socket
must be a Socket instance previously created by socket_create(). -
data
-
The data received will be fetched to the variable specified with
data
. -
length
-
Up to
length
bytes will be fetched from remote host. -
flags
-
The value of
flags
can be any combination of the following flags, joined with the binary OR (|
) operator.Possible values for flags
Flag Description MSG_OOB
Process out-of-band data. MSG_PEEK
Receive data from the beginning of the receive queue without removing it from the queue. MSG_WAITALL
Block until at least length
are received. However, if a signal is caught or the remote host disconnects, the function may return less data.MSG_DONTWAIT
With this flag set, the function returns even if it would normally have blocked. -
address
-
If the socket is of the type
AF_UNIX
type,address
is the path to the file. Else, for unconnected sockets,address
is the IP address of, the remote host, ornull
if the socket is connection-oriented. -
port
-
This argument only applies to
AF_INET
andAF_INET6
sockets, and specifies the remote port from which the data is received. If the socket is connection-oriented,port
will benull
.
Return Values
socket_recvfrom() returns the number of bytes received,
or false
if there was an error. The actual error code can be retrieved by
calling socket_last_error(). This error code may be
passed to socket_strerror() to get a textual explanation
of the error.
Changelog
Version | Description |
---|---|
8.0.0 |
socket is a Socket instance now;
previously, it was a resource.
|
Examples
Example #1 socket_recvfrom() example
<?php
$socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
socket_bind($socket, '127.0.0.1', 1223);
$from = '';
$port = 0;
socket_recvfrom($socket, $buf, 12, 0, $from, $port);
echo "Received $buf from remote address $from and remote port $port" . PHP_EOL;
?>
This example will initiate a UDP socket on port 1223 of 127.0.0.1 and print at most 12 characters received from a remote host.
See Also
- socket_recv() - Receives data from a connected socket
- socket_send() - Sends data to a connected socket
- socket_sendto() - Sends a message to a socket, whether it is connected or not
- socket_create() - Create a socket (endpoint for communication)