wp_cache_add()

wp_cache_add() — Adds data to the cache, if the cache key doesn’t already exist.

Inputs: $key (int|string): The cache key to use for retrieval later. $data (mixed): The data to add to the cache. $group (string): Optional. The group to add the cache to. Enables the same key to be used across groups. Default empty. $expire (int): Optional. When the cache data should expire, in seconds. Default 0 (no expiration).

Returns bool: True on success, false if cache key and group already exist.