Check if PHP session has already started

php, session, session-variables

Solution

Recommended way for versions of PHP >= 5.4.0 , PHP 7, PHP 8

if (session_status() === PHP_SESSION_NONE) {
    session_start();
}

Reference: http://www.php.net/manual/en/function.session-status.php

For versions of PHP < 5.4.0

if(session_id() == '') {
    session_start();
}

Problem

I have a PHP file that is sometimes called from a page that has started a session and sometimes from a page that doesn't have session started. Therefore when I have `session_start()` on this script I sometimes get the error message for "session already started". For that I've put these lines: ``` if(!isset($_COOKIE["PHPSESSID"])) { session_start(); } ``` but this time I got this warning message: Notice: Undefined variable: _SESSION Is there a better way to check if session has already started? If I use `@session_start` will it make things work properly and just shut up the warnings?

Original source

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