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функция не описана

wp_using_themes() WP 5.1.0

Determines whether the current request should use themes.

Хуки из функции
Возвращает

true/false. True if themes should be used, false otherwise.

Использование

wp_using_themes();

Код wp using themes: wp-includes/load.php WP 5.2.2

<?php
function wp_using_themes() {
	/**
	 * Filters whether the current request should use themes.
	 *
	 * @since 5.1.0
	 *
	 * @param bool $wp_using_themes Whether the current request should use themes.
	 */
	return apply_filters( 'wp_using_themes', defined( 'WP_USE_THEMES' ) && WP_USE_THEMES );
}