Vulkan Cookbook

How it works...

The command pool is destroyed with the following code:

if( VK_NULL_HANDLE != command_pool ) { 
  vkDestroyCommandPool( logical_device, command_pool, nullptr ); 
  command_pool = VK_NULL_HANDLE; 
}

But, we can't destroy the pool until all command buffers allocated from it are not pending for execution on a device. To do that, we can wait on fences or use one of the functions that causes the application to wait until the selected queue stops processing commands, or while the whole device is busy (the work submitted to all queues from a given device is still being processed). Only then can we safely destroy the command pool.