update_post_meta ( $post_id, $meta_key, $meta_value, $prev_value = '' )
- (int) $post_id Post ID.
- (string) $meta_key Metadata key.
- (mixed) $meta_value Metadata value. Must be serializable if non-scalar.
- (mixed) $prev_value Optional. Previous value to check before updating.
- (int|bool) The new meta field ID if a field with the given key didn't exist and was therefore added, true on successful update, false on failure.
- Introduced in WordPress: 1.5.0
- Deprecated in WordPress: —
Updates a post meta field based on the given post ID.
$prev_value parameter to differentiate between meta fields with the
same key and post ID.
If the meta field for the post does not exist, it will be added and its ID returned.
Can be used in place of add_post_meta().