Module latch

Structs

CoreLatch 🔒

Spin latches are the simplest, most efficient kind, but they do not support a wait() operation. They just have a boolean flag that becomes true when set() is called.

CountLatch 🔒

Counting latches are used to implement scopes. They track a counter. Unlike other latches, calling set() does not necessarily make the latch be considered set(); instead, it just decrements the counter. The latch is only “set” (in the sense that probe() returns true) once the counter reaches zero.

LatchRef 🔒

&L without any implication of dereferenceable for Latch::set

LockLatch 🔒

A Latch starts as false and eventually becomes true. You can block until it becomes true.

OnceLatch 🔒

Once latches are used to implement one-time blocking, primarily for the termination flag of the threads in the pool.

SpinLatch 🔒

Spin latches are the simplest, most efficient kind, but they do not support a wait() operation. They just have a boolean flag that becomes true when set() is called.

Enums

CountLatchKind 🔒

Constants

SET 🔒

Latch is set.

SLEEPING 🔒

Latch is not set, owning thread is asleep on this latch and must be awoken.

SLEEPY 🔒

Latch is not set, owning thread is going to sleep on this latch (but has not yet fallen asleep).

UNSET 🔒

Latch is not set, owning thread is awake

Traits

AsCoreLatch 🔒

Latch 🔒

We define various kinds of latches, which are all a primitive signaling mechanism. A latch starts as false. Eventually someone calls set() and it becomes true. You can test if it has been set by calling probe().