Initiates a socket connection to the resource specified by
target. PHP supports
targets in the Internet and Unix domains as described in
Appendix P. A list of supported transports
can also be retrieved using stream_get_transports().
Note: If you need to set a timeout for reading/writing data over the socket, use stream_set_timeout(), as the
timeoutparameter to fsockopen() only applies while connecting the socket.
As of PHP 4.3.0, if you have compiled in OpenSSL support, you may
hostname with either
'ssl://' or 'tls://' to
use an SSL or TLS client connection over TCP/IP to connect
to the remote host.
If the call fails, it will return FALSE and if the optional
arguments are present they will be set to indicate the actual
system level error that occurred in the system-level
connect() call. If the value returned in
errno is 0 and the
function returned FALSE, it is an indication that the error
occurred before the connect() call. This is
most likely due to a problem initializing the socket. Note that
errstr arguments will always be passed by
Depending on the environment, the Unix domain or the optional connect timeout may not be available.
The socket will by default be opened in blocking mode. You can switch it to non-blocking mode by using stream_set_blocking().
Example 1. fsockopen() Example
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.
Note: When specifying a numerical IPv6 address (e.g. fe80::1) you must enclose the IP in square brackets. For example, tcp://[fe80::1]:80.
Note: The timeout parameter was introduced in PHP 3.0.9 and UDP support was added in PHP 4.