Retrieves, but does not remove, the head (first element) of this list.
Documentation
Retrieves, but does not remove, the head (first element) of this list.
This method has a time complexity of O(1).
Parameters:
list - The list to use
Returns:
void * retptr != (void*)-1: The first element of this list, may be NULL.
void * retptr == (void*)-1: An error, see pbl_errno:
PBL_ERROR_OUT_OF_BOUNDS - this list is empty.
