int fsockopen (string [udp://]hostname, int port [, int
errno [, string
errstr [, double
Initiates a stream connection in the Internet (AF_INET, using TCP or UDP) or Unix (AF_UNIX) domain. For the Internet domain, it will open a TCP socket connection to hostname on port port. hostname may in this case be either a fully qualified domain name or an IP address. For UDP connections, you need to explicitly specify the protocol: udp://hostname. For the Unix domain, hostname will be used as the path to the socket, port must be set to 0 in this case. The optional timeout can be used to set a timeout in seconds for the connect system call.
If the call fails, it will return false and if the optional errno and errstr arguments are present they will be set to indicate the actual system level error that occurred on the system-level connect() call. If the returned 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 the errno and errstr arguments must be passed by reference.
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 socket_set_blocking().
Note: The timeout parameter was introduced in PHP 3.0.9 and UDP support was added in PHP 4.