is_protected_meta() │ WP 3.1.3

Determines whether a meta key is protected (internal).

WordPress uses the following mechanism: if the name of the meta key starts with an underscore _, for example, _edit_time, then it's considered as protected - it means this meta key is used for internal purposes, so the protected meta keys are not displayed in the Custom Fields panel when editing a post.

1 time — 0.00001 sec (speed of light) | 50000 times — 0.03 sec (speed of light) | PHP 7.0.8, WP 4.6

Hooks from the function

is_protected_meta

Return

true|false. Whether the meta key is considered protected.

Usage

is_protected_meta( $meta_key, $meta_type );

$meta_key(string) (required): Metadata key.
$meta_type(string): Type of object metadata is for. Accepts 'post', 'comment', 'term', 'user', or any other object type with an associated meta table.
Default: empty string

Examples

#1 Check whether it is a protected meta key

$meta_key = '_my_metakey';
if( is_protected_meta( $meta_key, 'post' ) ){
	echo 'Protected meta key';
}

Changelog

Since 3.1.3

Introduced.

`is_protected_meta() is protected meta` code ^{WP 6.5.2}

wp-includes/meta.php

function is_protected_meta( $meta_key, $meta_type = '' ) {
	$sanitized_key = preg_replace( "/[^\x20-\x7E\p{L}]/", '', $meta_key );
	$protected     = strlen( $sanitized_key ) > 0 && ( '_' === $sanitized_key[0] );

	/**
	 * Filters whether a meta key is considered protected.
	 *
	 * @since 3.2.0
	 *
	 * @param bool   $protected Whether the key is considered protected.
	 * @param string $meta_key  Metadata key.
	 * @param string $meta_type Type of object metadata is for. Accepts 'post', 'comment', 'term', 'user',
	 *                          or any other object type with an associated meta table.
	 */
	return apply_filters( 'is_protected_meta', $protected, $meta_key, $meta_type );
}