H5Mexists

herr_t H5Mexists(
       hid_t map_id,
       hid_t key_mem_type_id,
       const(void) *  key,
       hbool_t *  exists,
       hid_t mapl_id
   )

Checks if a key exists in a map.

`map_id`	Map identifier
`key_mem_type_id`	Memory datatype of the key
`key`	Pointer to the key data
`exists`	Pointer to receive the existence flag
`mapl_id`	Map access property list identifier, or H5P_DEFAULT

Non-negative on success, negative on failure.