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function is not described

_wp_timezone_choice_usort_callback() WP 2.9.0

Sort-helper for timezones.

This is an internal function for using it by WP core itself. It's not recommended to use this function in your code.

No Hooks.

Return

Int. Null. Nothing.

Usage

_wp_timezone_choice_usort_callback( $a, $b );
$a(array) (required)
-
$b(array) (required)
-

Changelog

Since 2.9.0 Introduced.

Code of _wp_timezone_choice_usort_callback() WP 5.7

<?php
function _wp_timezone_choice_usort_callback( $a, $b ) {
	// Don't use translated versions of Etc.
	if ( 'Etc' === $a['continent'] && 'Etc' === $b['continent'] ) {
		// Make the order of these more like the old dropdown.
		if ( 'GMT+' === substr( $a['city'], 0, 4 ) && 'GMT+' === substr( $b['city'], 0, 4 ) ) {
			return -1 * ( strnatcasecmp( $a['city'], $b['city'] ) );
		}
		if ( 'UTC' === $a['city'] ) {
			if ( 'GMT+' === substr( $b['city'], 0, 4 ) ) {
				return 1;
			}
			return -1;
		}
		if ( 'UTC' === $b['city'] ) {
			if ( 'GMT+' === substr( $a['city'], 0, 4 ) ) {
				return -1;
			}
			return 1;
		}
		return strnatcasecmp( $a['city'], $b['city'] );
	}
	if ( $a['t_continent'] == $b['t_continent'] ) {
		if ( $a['t_city'] == $b['t_city'] ) {
			return strnatcasecmp( $a['t_subcity'], $b['t_subcity'] );
		}
		return strnatcasecmp( $a['t_city'], $b['t_city'] );
	} else {
		// Force Etc to the bottom of the list.
		if ( 'Etc' === $a['continent'] ) {
			return 1;
		}
		if ( 'Etc' === $b['continent'] ) {
			return -1;
		}
		return strnatcasecmp( $a['t_continent'], $b['t_continent'] );
	}
}