5.6 Atomic Execution
| (require ffi/unsafe/atomic) |
| |
|
Disables and enables context switches at the level of Racket
threads. Calls to start-atomic and end-atomic can be
nested.
Using call-as-atomic is somewhat safer, in that call-as-atomic correctly catches exceptions and re-raises them after exiting atomic mode. For simple uses, however, start-atomic and end-atomic are faster.
| (call-as-atomic thunk) → any |
| thunk : (-> any) |
Calls thunk in atomic mode. If thunk raises and
exception, the exception is caught and re-raised after exiting atomic
mode.
When call-as-atomic is used in the dynamic extent of call-as-atomic, then thunk is simply called directly (as a tail call).
| (call-as-nonatomic thunk) → any |
| thunk : (-> any) |
Within the dynamic extent of a call-as-atomic, calls
thunk in non-atomic mode. Beware that the current thread
maybe suspended or terminated by other threads during thunk,
in which case the call never returns.
When used not in the dynamic extent of call-as-atomic, call-as-nonatomic raises exn:fail:contract.