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<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision: 297028 $ -->
<refentry xml:id="function.stream-socket-client" xmlns="http://docbook.org/ns/docbook">
<refnamediv>
<refname>stream_socket_client</refname>
<refpurpose>Open Internet or Unix domain socket connection</refpurpose>
</refnamediv>
<refsect1 role="description">
&reftitle.description;
<methodsynopsis>
<type>resource</type><methodname>stream_socket_client</methodname>
<methodparam><type>string</type><parameter>remote_socket</parameter></methodparam>
<methodparam choice="opt"><type>int</type><parameter role="reference">errno</parameter></methodparam>
<methodparam choice="opt"><type>string</type><parameter role="reference">errstr</parameter></methodparam>
<methodparam choice="opt"><type>float</type><parameter>timeout</parameter><initializer>ini_get("default_socket_timeout")</initializer></methodparam>
<methodparam choice="opt"><type>int</type><parameter>flags</parameter><initializer>STREAM_CLIENT_CONNECT</initializer></methodparam>
<methodparam choice="opt"><type>resource</type><parameter>context</parameter></methodparam>
</methodsynopsis>
<para>
Initiates a stream or datagram connection to the destination specified
by <parameter>remote_socket</parameter>. The type of socket created
is determined by the transport specified using standard URL formatting:
<literal>transport://target</literal>. For Internet Domain sockets
(AF_INET) such as TCP and UDP, the <literal>target</literal> portion
of the <parameter>remote_socket</parameter> parameter should consist of
a hostname or IP address followed by a colon and a port number. For Unix
domain sockets, the <parameter>target</parameter> portion should point
to the socket file on the filesystem.
</para>
<note>
<para>
The stream will by default be opened in blocking mode. You can
switch it to non-blocking mode by using
<function>stream_set_blocking</function>.
</para>
</note>
</refsect1>
<refsect1 role="parameters"><!-- {{{ -->
&reftitle.parameters;
<para>
<variablelist>
<varlistentry>
<term><parameter>remote_socket</parameter></term>
<listitem>
<para>
Address to the socket to connect to.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>errno</parameter></term>
<listitem>
<para>
Will be set to the system level error number if connection fails.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>errstr</parameter></term>
<listitem>
<para>
Will be set to the system level error message if the connection fails.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>timeout</parameter></term>
<listitem>
<para>
Number of seconds until the <literal>connect()</literal> system call
should timeout.
<note>
<simpara>
This parameter only applies when not making asynchronous
connection attempts.
</simpara>
</note>
<note>
<para>
To set a timeout for reading/writing data over the socket, use the
<function>stream_set_timeout</function>, as the
<parameter>timeout</parameter> only applies while making connecting
the socket.
</para>
</note>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>flags</parameter></term>
<listitem>
<para>
Bitmask field which may be set to any combination of connection flags.
Currently the select of connection flags is limited to
<constant>STREAM_CLIENT_CONNECT</constant> (default),
<constant>STREAM_CLIENT_ASYNC_CONNECT</constant> and
<constant>STREAM_CLIENT_PERSISTENT</constant>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>context</parameter></term>
<listitem>
<para>
A valid context resource created with <function>stream_context_create</function>.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1><!-- }}} -->
<refsect1 role="returnvalues"><!-- {{{ -->
&reftitle.returnvalues;
<para>
On success a stream resource is returned which may
be used together with the other file functions (such as
<function>fgets</function>, <function>fgetss</function>,
<function>fwrite</function>, <function>fclose</function>, and
<function>feof</function>), &false; on failure.
</para>
</refsect1><!-- }}} -->
<refsect1 role="errors"><!-- {{{ -->
&reftitle.errors;
<para>
On failure the <parameter>errno</parameter> and
<parameter>errstr</parameter> arguments will be populated with the actual
system level error that occurred in the system-level
<literal>connect()</literal> call. If the value returned in
<parameter>errno</parameter> is <literal>0</literal> and the
function returned &false;, it is an indication that the error
occurred before the <literal>connect()</literal> call. This is
most likely due to a problem initializing the socket. Note that
the <parameter>errno</parameter> and
<parameter>errstr</parameter> arguments will always be passed by
reference.
</para>
</refsect1><!-- }}} -->
<refsect1 role="examples"><!-- {{{ -->
&reftitle.examples;
<para>
<example xml:id="stream-socket-client.example.basic"><!-- {{{ -->
<title><function>stream_socket_client</function> example</title>
<programlisting role="php">
<![CDATA[
<?php
$fp = stream_socket_client("tcp://www.example.com:80", $errno, $errstr, 30);
if (!$fp) {
echo "$errstr ($errno)<br />\n";
} else {
fwrite($fp, "GET / HTTP/1.0\r\nHost: www.example.com\r\nAccept: */*\r\n\r\n");
while (!feof($fp)) {
echo fgets($fp, 1024);
}
fclose($fp);
}
?>
]]>
</programlisting>
</example><!-- }}} -->
<example xml:id="stream-socket-client.example.daytime"><!-- {{{ -->
<title>Using UDP connection</title>
<para>
Retrieving the day and time from the UDP service "daytime" (port 13)
on localhost.
</para>
<programlisting role="php">
<![CDATA[
<?php
$fp = stream_socket_client("udp://127.0.0.1:13", $errno, $errstr);
if (!$fp) {
echo "ERROR: $errno - $errstr<br />\n";
} else {
fwrite($fp, "\n");
echo fread($fp, 26);
fclose($fp);
}
?>
]]>
</programlisting>
</example><!-- }}} -->
</para>
</refsect1><!-- }}} -->
<refsect1 role="notes"><!-- {{{ -->
&reftitle.notes;
<warning>
<simpara>
UDP sockets will sometimes appear to have opened without an error,
even if the remote host is unreachable. The error will only
become apparent when you read or write data to/from the socket.
The reason for this is because UDP is a "connectionless" protocol,
which means that the operating system does not try to establish
a link for the socket until it actually needs to send or receive data.
</simpara>
</warning>
&ipv6.brackets;
<note>
<para>
Depending on the environment, the Unix domain or the optional
connect timeout may not be available. A list of available
transports can be retrieved using <function>stream_get_transports</function>.
See <xref linkend="transports"/> for a list of built in transports.
</para>
</note>
</refsect1><!-- }}} -->
<refsect1 role="seealso"><!-- {{{ -->
&reftitle.seealso;
<para>
<simplelist>
<member><function>stream_socket_server</function></member>
<member><function>stream_set_blocking</function></member>
<member><function>stream_set_timeout</function></member>
<member><function>stream_select</function></member>
<member><function>fgets</function></member>
<member><function>fgetss</function></member>
<member><function>fwrite</function></member>
<member><function>fclose</function></member>
<member><function>feof</function></member>
<member><xref linkend="ref.curl" /></member>
</simplelist>
</para>
</refsect1><!-- }}} -->
</refentry>
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