Checks whether the given variable is a WordPress Error.

Load the database class file and instantiate the $wpdb global.

Runs just before PHP shuts down execution.

Get the time elapsed so far during this PHP script.

Start the WordPress micro-timer.

Retrieve or display the time from the page start to when function is called.

Check for the required PHP version, and the MySQL extension or a database drop-in.

Copy an object.

Converts a shorthand byte value to an integer byte value.

Set PHP error reporting based on WordPress debug settings.