session_id is used to get or set the session id for the current session.
The constant SID can also be used to retrieve the current name and session id as a string suitable for adding to URLs. See also Session handling.
If id is specified and not null, it will replace the current session id. session_id needs to be called before session_start for that purpose. Depending on the session handler, not all characters are allowed within the session id. For example, the file session handler only allows characters in the range a-z A-Z 0-9 , (comma) and - (minus)!
When using session cookies, specifying an id for session_id will always send a new cookie when session_start is called, regardless if the current session id is identical to the one being set.
session_id returns the session id for the current session or the empty string ("") if there is no current session (no current session id exists). On failure, false is returned.
|8.0.0||id is nullable now.|