In ________, a cancellation request may take effect without waiting for the…

Concept

Thread cancellation uses a cancellation state and a cancellation type to control whether and when a pending request takes effect.

With asynchronous cancellation, the request may be acted on at any time. With deferred cancellation, it remains pending until the target reaches a defined cancellation point.

Application

1. The stem says the request need not wait for the target thread to reach a cancellation point.

2. That timing rule is the defining behavior of asynchronous cancellation.

3. Therefore, the blank is filled by “asynchronous cancellation.”

Contrast and cross-check

• Synchronous cancellation is not one of the two POSIX cancellation types; it suggests a coordinated request-response action.

• Deferred cancellation waits for the target to reach a cancellation point.

• “Both deferred and asynchronous cancellation” combines two distinct timing policies instead of naming the single policy described.

Cross-check: POSIX defines the two cancellation types as asynchronous and deferred, and the at-any-time behavior belongs to the asynchronous type.