How does including PHP subfiles with session_start() affect the session ID and session data in PHP applications?

When including PHP subfiles with `session_start()`, it can lead to unexpected behavior as each included file may call `session_start()` multiple times, resulting in multiple session IDs being generated and potentially overwriting session data. To solve this issue, you can check if the session has already started before calling `session_start()` in each included file. 

// Include this code at the beginning of each PHP subfile
if(session_status() == PHP_SESSION_NONE) {
    session_start();
}

Keywords

PHP subfiles session_start() session ID session data

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