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I want to get he windows system username if my file was on the server. Because currently it is giving me my hosting server username.
I tried getenv(),$_SERVER['AUTH_USER'],get_current_user() but none of these giving me the windows system username. When i am using the getenv() in localhost it is showing the system username, but not on the server.
Is it possible through PHP or not?
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When you access the PHP on the server, there are 2 users involved. The hosting server's user under which the PHP is executed on the server, and your local computer user in which your browser is running.
From your question it appears like you're trying to get the username of your local computer where you run your browser. This is not possible.
When the PHP is hosted on a server you only have access to the hosting server username.