only the pointer to the data is stored in the hash table
no space is malloced for the data!
Parameters:
h - hash table to insert to
key - key to insert
keylen - length of that key
dataptr - dataptr to insert
Returns:
int ret == 0: ok
int ret == -1: an error, see pbl_errno:
PBL_ERROR_EXISTS: an item with the same key already exists
PBL_ERROR_OUT_OF_MEMORY: out of memory