[PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8]
socket_recv — Receives data from a connected socket
Description
socket_recv[
Socket $socket,
?string
&$data,
int $length,
int $flags
]: int|false
data is passed by reference, so it must be specified as a variable in the argument list. Data read from socket by socket_recv[] will be returned in data.
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. If an error occurs, if the connection is reset, or if no data is available, data will be set to null.
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.
flagsMSG_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. |
Return Values
socket_recv[] 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
| 8.0.0 | socket is a Socket instance now; previously, it was a resource.
|
Examples
Example #1 socket_recv[] example
This example is a simple rewrite of the first example from Examples to use socket_recv[].
The above example will produce something like:
TCP/IP Connection
OK. Attempting to connect to '208.77.188.166' on port '80'...OK. Sending HTTP HEAD request...OK. Reading response: Read 123 bytes from socket_recv[]. Closing socket...HTTP/1.1 200 OK Date: Mon, 14 Sep 2009 08:56:36 GMT Server: Apache/2.2.3 [Red Hat] Last-Modified: Tue, 15 Nov 2005 13:24:10 GMT ETag: "b80f4-1b6-80bfd280" Accept-Ranges: bytes Content-Length: 438 Connection: close Content-Type: text/html; charset=UTF-8 OK.
dgk at tcde dot ru ¶
17 years ago
I've used socket_select and socket_recv with a while loop and found myself in trouble when remote side closed connection. The code below produced infinite loop and socket_select returned immediately [which lead to high cpu time consumption].
The solution was simple, but quite hard to find because socket_recv is not documented. socket_recv returns FALSE if there is no data and 0 if the socket is widowed [disconnected by remote side]. So I had just to check return value of socket_recv. The problem now sounds stupid, but I've spend some time to find it out.
I hope this will save some of somebody's hair ;]
m_lajos at hotmail dot com ¶
8 years ago
Workaround for the missing MSG_DONTWAIT flag according to the bug report page:
ss-130 at yandex dot ru ¶
9 years ago
rathamahata at rathamahata dot net ¶
17 years ago
It looks like that mysterious flags are just the recv[2] flags passed to your OS syscall and nothing more...
ext/sockets/sockets.c:PHP_FUNCTION[socket_recv]
...
if [[retval = recv[php_sock->bsd_socket, recv_buf, len, flags]] < 1] {
efree[recv_buf];
...
for linux you can type `man 2 recv' and you will see complete description of thouse flags.
Sergey S. Kosrtyliov
//www.rathamahata.net/
bastiaan at [no-spam] megabass dot nl ¶
18 years ago
in case you want to empty/unset $buffer, but failing to do so, try using 0 as flag.
PHP_NORMAL_READ and PHP_BINARY_READ respectively hold 1 and 2 as value.
lexkrstn at gmail dot com ¶
3 years ago
It seems like the flags are just passed to the underlying recv[] function of your OS, hence there no MSG_DONTWAIT flag on Windows and you should not define it yourself in that case, it just won't work.
Anonymous ¶
1 year ago