socket_sendmsg

(PHP 5 >= 5.5.0, PHP 7, PHP 8)

socket_sendmsg — Send a message

说明

function socket_sendmsg(Socket $socket, array $message, int $flags = 0): int|false

The function socket_sendmsg() sends the message described by message through the socket socket, using the sendmsg() system call.

参数

socket

A Socket instance created with socket_create(), socket_accept() or socket_create_pair().

message

An associative array which may contain the following elements. All of them are optional, and unrecognized keys are silently ignored. In particular there is no flags element when sending; that key only appears in the array filled in by socket_recvmsg().

name

The address of the remote host, as an array. Its keys are addr and port for AF_INET; addr, port, flowinfo and scope_id for AF_INET6; and path for AF_UNIX. addr accepts an IP address or a host name, which is then resolved. An optional family key selects the address family explicitly; if omitted, the family of socket is used. A family the socket does not support makes the call fail.

iov

A list of buffers holding the data to send, which are sent in order as a single message. Array keys are ignored and the values are converted to string. When this key is missing or empty, no data is sent and the function returns 0.

control

A list of ancillary data messages. Each is an array with the keys level, type and data. Only the pairs below are supported, and their availability depends on the platform.

Supported ancillary data
level type data
SOL_SOCKET SCM_RIGHTS A non-empty list of Socket instances or stream resources, whose file descriptors are sent to the receiving process.
SOL_SOCKET SCM_CREDENTIALS An array with the keys pid, uid and gid. Named SCM_CREDS or SCM_CREDS2 on some systems.
IPPROTO_IPV6 IPV6_PKTINFO An array with the keys addr and ifindex.
IPPROTO_IPV6 IPV6_HOPLIMIT An int.
IPPROTO_IPV6 IPV6_TCLASS An int.
flags

The value of flags can be any combination of the following flags, joined with the binary OR (|) operator.

Possible values for flags
MSG_OOB Send OOB (out-of-band) data.
MSG_EOR Indicate a record mark. The sent data completes the record.
MSG_DONTWAIT With this flag set, the function returns even if it would normally have blocked.
MSG_DONTROUTE Bypass routing, use direct interface.

返回值

Returns the number of bytes sent, 或者在失败时返回 false.

更新日志

版本 说明
8.0.0 现在 socket 是 Socket 实例， 之前是 resource。

示例

示例 #1 Sending a message with socket_sendmsg()

<?php
$server = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
socket_bind($server, '127.0.0.1', 1053);

$client = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
$sent = socket_sendmsg($client, [
    'name' => ['addr' => '127.0.0.1', 'port' => 1053],
    'iov'  => ['Hello ', 'world'],
], 0);

echo "sent: $sent\n";

socket_recvfrom($server, $buffer, 64, 0, $from, $port);
echo "received: $buffer\n";
?>

以上示例会输出：

sent: 11
received: Hello world

示例 #2 Passing a file descriptor over a UNIX socket

The control key carries ancillary data. With SCM_RIGHTS, it transfers open file descriptors to the process at the other end of a UNIX socket. This is not available on Windows. 

<?php
socket_create_pair(AF_UNIX, SOCK_STREAM, 0, $pair);
[$sender, $receiver] = $pair;

$file = fopen(__FILE__, 'r');

socket_sendmsg($sender, [
    // At least one byte of regular data must accompany the ancillary data.
    'iov'     => ['fd'],
    'control' => [
        ['level' => SOL_SOCKET, 'type' => SCM_RIGHTS, 'data' => [$file]],
    ],
], 0);

$message = [
    'buffer_size' => 16,
    'controllen'  => socket_cmsg_space(SOL_SOCKET, SCM_RIGHTS, 1),
];
socket_recvmsg($receiver, $message, 0);

$received = $message['control'][0]['data'][0];
echo "first line: ", fgets($received);
?>

以上示例会输出：

first line: <?php

参见

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