/**
* Finds a node with a given key. If it does not exist, a new one is created.
* It is strongly recommended to use <<give_init_data,`HASH_GIVE_INIT_DATA`>>.
*
* This one is enabled by the <<want_lookup,`HASH_WANT_LOOKUP`>> macro.
/**
* Finds a node with a given key. If it does not exist, a new one is created.
* It is strongly recommended to use <<give_init_data,`HASH_GIVE_INIT_DATA`>>.
*
* This one is enabled by the <<want_lookup,`HASH_WANT_LOOKUP`>> macro.