For hash sets his method has a time complexity of O(1).
For tree sets his method has a time complexity of O(Log N).
Parameters:
set - The set to add to
element - Element to be added to this set
Returns:
int rc > 0: The set did not already contain the specified element.
int rc == 0: The set did already contain the specified element.
int rc < 0: An error, see pbl_errno:
PBL_ERROR_OUT_OF_MEMORY - Out of memory.
PBL_ERROR_PARAM_ELEMENT - The element passed is NULL.
PBL_ERROR_OUT_OF_BOUNDS - Maximum capacity of the hash set exceeded.