session_id

Function • Params and return types changed in PHP 8.0

Get and/or set the current session id.

PHP 5
PHP 7
PHP 8.0
Improved
PHP 8.1
PHP 8.2-8.3
PHP 8.4
PHP 8.5
PHP 8.6

session_id Function synopsis

session_id(?string $id = null): string|false

Parameters

$id

OptionalType?stringDefault valuenull

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-zA-Z0-9,-]!

Return value

Typestring|false

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.

Changes to the session_id Function

PHP 8.0

  • Return type added: string|false
  • Parameter type added for parameter #1 ($id): ?string
  • Parameter default value added for position #1 ($id): null
- session_id($id)
+ session_id(?string $id = null): string|false

session_id Function Availability

PHP VersionAvailability
PHP 8.6Upcoming Release Yes
PHP 8.5Supported (Latest) Yes
PHP 8.4Supported Yes
PHP 8.3Security-Fixes Only Yes
PHP 8.2Security-Fixes Only Yes
PHP 8.1Unsupported Yes
PHP 8.0Unsupported Yes
PHP 7.4Unsupported Yes
PHP 7.3Unsupported Yes
PHP 7.2Unsupported Yes
PHP 7.1Unsupported Yes
PHP 7.0Unsupported Yes
PHP 5.6Unsupported Yes
PHP 5.5Unsupported Yes
PHP 5.4Unsupported Yes
PHP 5.3Unsupported Yes