acf/pre_save_post │ filter-hook │ ACF 1.0

Usage

add_filter( 'acf/pre_save_post', 'wp_kama_acf_pre_save_post_filter', 10, 2 );

/**
 * Function for `acf/pre_save_post` filter-hook.
 * 
 * @param  $post_id 
 * @param  $form    
 *
 * @return 
 */
function wp_kama_acf_pre_save_post_filter( $post_id, $form ){
	// filter...
	return $post_id;
}

$post_id

-

$form

-

Where the hook is called

$post_id = apply_filters( 'acf/pre_save_post', $post_id, $form );

Where the hook is used in Advanced Custom Fields PRO

add_filter( 'acf/pre_save_post', array( $this, 'pre_save_post' ), 5, 2 );