Removes the mapping for this string key from this map if it is present.
Removes the mapping for this string key from this map if it is present.More formally, if this map contains a mapping from a key k to a value v such that (key==null ? k==null : memcmp( key, k, keyLength ) == 0, that mapping is removed. (The map can contain at most one such mapping.)
Returns the previous value associated with key, NULL if there was no mapping for key or (void*)-1 in case of an error.
Note: If a valid pointer to a value is returned, the value returned is malloced on the heap. It is the caller's responsibility to free that memory once it is no longer needed.
For hash maps this method has a time complexity of O(1). For tree maps this method has a time complexity of O(Log N).