Getting the Current User

1. Call the function get_currentuserinfo() on the next line after declaring the global variable $current_user

2. What is the difference between wp_get_current_user() and get_currentuserinfo()?

Below is a snippet:

function wp_get_current_user() {

    global $current_user;

    get_currentuserinfo();

    return $current_user;
}

I think the source code answers your first two questions, right?

Remember that wp_get_current_user() is defined in wp-includes/pluggable.php so it can be overridden.

Also, it is safe to stick with global $current_user this is because WordPress calls wp_get_current_user() during initialization.

Specifically, wp-settings.php -> new WP -> WP->init() -> wp_get_current_user

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The usage of $profileuser, this global variable is only available when you are editing a user (user-edit.php) and the data will be thereof.

The last one questions I don’t really know how to answer so I’ll leave to others.

Hope you don’t mind.