session_start()

session_start() — Start new or resume existing session.

session_start creates a session or resumes the current one based on a session identifier passed via a GET or POST request, or passed via a cookie.

When session_start is called or when a session auto starts, PHP will call the open and read session save handlers. These will either be a built-in save handler provided by default or by PHP extensions (such as SQLite or Memcached); or can be custom handler as defined by session_set_save_handler. The read callback will retrieve any existing session data (stored in a special serialized format) and will be unserialized and used to automatically populate the $_SESSION superglobal when the read callback returns the saved session data back to PHP session handling.

Inputs: options: If provided, this is an associative array of options that will override the currently set session configuration directives. The keys should not include the session. prefix. In addition to the normal set of configuration directives, a read_and_close option may also be provided.

Returns: This function returns true if a session was successfully started, otherwise false.