vkInvalidateMappedMemoryRanges

vkInvalidateMappedMemoryRanges is a Vulkan API function used to invalidate host memory caches for specified ranges of memory that have been mapped from a device memory object. It is designed for memory that is host-visible but non-coherent, where the device may write data that the CPU would not automatically see without explicit invalidation.

The function takes a device, a count of memory ranges, and an array of VkMappedMemoryRange structures describing the ranges to invalidate. Each VkMappedMemoryRange specifies the VkDeviceMemory object, the offset and size of the range, and a pNext pointer for extension chaining. The ranges must refer to memory that has been previously mapped with vkMapMemory. Invalidation forces the host to refresh its cached view of the memory contents so subsequent reads by the CPU observe any writes performed by the device.

vkInvalidateMappedMemoryRanges is typically used after the device has written to memory that the host will read, and before the host reads, in non-coherent memory scenarios. It is often used in conjunction with vkFlushMappedMemoryRanges, which ensures that host writes are visible to the device. For memory that is coherent, invalidation may have no effect because changes are automatically visible to the host.

Return values indicate success or specific errors, such as VK_ERROR_OUT_OF_HOST_MEMORY or VK_ERROR_MEMORY_MAP_FAILED, with VK_SUCCESS indicating the ranges were invalidated. This function helps synchronize data between device-side operations and host-side reads in applications that rely on mapped, non-coherent memory.