C Specification

Semaphores are a synchronization primitive that can be used to insert a dependency between batches submitted to queues. Semaphores have two states - signaled and unsignaled. The state of a semaphore can be signaled after execution of a batch of commands is completed. A batch can wait for a semaphore to become signaled before it begins execution, and the semaphore is also unsignaled before the batch begins execution.

Semaphores are represented by VkSemaphore handles:

VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkSemaphore)