This section describes the conventions and notations in the UCX specification.

Blocking Behavior

The blocking UCX routines return only when a UCX operation is complete. After the return, the resources used in the UCX routine are available for reuse.

Non-blocking Behavior

The non-blocking UCX routines return immediately, independent of operation completion. After the return, the resources used for the routines are not necessarily available for reuse.

Fairness

UCX routines do not guarantee fairness. However, the routines enable UCX consumers to write efficient and fair programs.

Interaction with Signal Handler Functions

If UCX routines are invoked from a signal handler function, the behavior of the program is undefined.