Initiates a stream or datagram connection to the destination specified
remote_socket. The type of socket created
is determined by the transport specified using standard URL formatting:
transport://target. For Internet Domain sockets
(AF_INET) such as TCP and UDP, the target portion
remote_socket parameter should consist of
a hostname or IP address followed by a colon and a port number. For Unix
domain sockets, the
target portion should point
to the socket file on the filesystem.
timeout can be used to
set a timeout in seconds for the connect system call.
flags is a bitmask field which may be set to any
combination of connection flags. Currently the selection of connection
flags is limited to STREAM_CLIENT_CONNECT (default),
Note: If you need to set a timeout for reading/writing data over the socket, use stream_set_timeout(), as the
timeoutparameter to stream_socket_client() only applies while connecting the socket.
Note: The timeout parameter only applies if you are not making an asynchronous connection attempt.
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. A list of available transports can be retrieved using stream_get_transports(). See Appendix P for a list of built in transports.
The stream will by default be opened in blocking mode. You can switch it to non-blocking mode by using stream_set_blocking().
Example 1. stream_socket_client() 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.