fsockopen()

fsockopen() — Open Internet or Unix domain socket connection.

Built-in function of PHP 8.5. The manual lists it as available in PHP 4, PHP 5, PHP 7, PHP 8. This page is the reference card: signature, parameters and return value, plus the changelog and the example the manual provides.

What it does

Initiates a socket connection to the resource specified by hostname.

Signature

fsockopen(string $hostname, int $port = -1, int &$error_code = null, string &$error_message = null, ?float $timeout = null): resource|false

Parameters

Parameter	Type	What it takes
$hostname	string	If OpenSSL support is installed, you may prefix the hostname with either ssl:// or tls:// to use an SSL or TLS client connection over TCP/IP to connect to the remote host.
$port	int	The port number. This can be omitted and skipped with -1 for transports that do not use ports, such as unix://.
&$error_code	int	If provided, holds the system level error number that occurred in the system-level connect() call.
&$error_message	string	The error message as a string.
$timeout	?float	The connection timeout, in seconds. When null, the default_socket_timeout php.ini setting is used.

Return value

fsockopen() returns a file pointer which may be used together with the other file functions (such as fgets(), fgetss(), fwrite(), fclose(), and feof()). If the call fails, it will return false

Example

A runnable snippet:

$fp = fsockopen("www.example.com", 80, $errno, $errstr, 30); if (!$fp) { echo "$errstr ($errno)<br />\n"; } else { $out = "GET / HTTP/1.1\r\n"; $out .= "Host: www.example.com\r\n"; $out .= "Connection: Close\r\n\r\n"; fwrite($fp, $out); while (!feof($fp)) { echo fgets($fp, 128); } fclose($fp); }

Changelog

Version	Change
8.0.0	timeout is nullable now.