get_handle_tuple — Retrieve a tuple associated with a key from a handle.
get_handle_tuple retrieves a tuple associated with the
Handle and returns it in
The list of keys supported by a handle can be queried with
Note that this operator is provided only for implementing generic
debug and inspection mechanisms.
The keys returned for certain handle types can change without notice.
Additionally, some handle types might not be supported by this operator.
Also, this operator is not optimized for performance.
To obtain more reliable information about a handle in a program, it is
strongly recommended to use the operators specialized for the particular
handle type, such as
Handle of which to get the key.
→(string / integer)
Key to get.
Number of elements: Key == 1
length(Key) > 0
→(string / integer / real)
Control value of the key.
If the parameters are valid, the operator
returns the value 2 (H_MSG_TRUE).
If the handle is invalid or does not support the given key, or if the
key references an iconic object instead of a tuple, an exception is raised.