vkMapMemory

To retrieve a host virtual address pointer to a region of a mappable memory object, call:

VkResult vkMapMemory(
    VkDevice device,
    VkDeviceMemory memory,
    VkDeviceSize offset,
    VkDeviceSize size,
    VkMemoryMapFlags flags,
    void** ppData);

• device is the logical device that owns the memory.
• memory is the VkDeviceMemory object to be mapped.
• offset is a zero-based byte offset from the beginning of the memory object.
• size is the size of the memory range to map, or VK_WHOLE_SIZE to map from offset to the end of the allocation.
• flags is a bitmask of VkMemoryMapFlagBits specifying additional parameters of the memory map operation.
• ppData is a pointer to a void* variable in which a host-accessible pointer to the beginning of the mapped range is returned. This pointer minus offset must be aligned to at least VkPhysicalDeviceLimits::minMemoryMapAlignment.

After a successful call to vkMapMemory the memory object memory is considered to be currently host mapped.

vkMapMemory does not check whether the device memory is currently in use before returning the host-accessible pointer. The application must guarantee that any previously submitted command that writes to this range has completed before the host reads from or writes to that range, and that any previously submitted command that reads from that range has completed before the host writes to that region (see here for details on fulfilling such a guarantee). If the device memory was allocated without the VK_MEMORY_PROPERTY_HOST_COHERENT_BIT set, these guarantees must be made for an extended range: the application must round down the start of the range to the nearest multiple of VkPhysicalDeviceLimits::nonCoherentAtomSize, and round the end of the range up to the nearest multiple of VkPhysicalDeviceLimits::nonCoherentAtomSize.

While a range of device memory is host mapped, the application is responsible for synchronizing both device and host access to that memory range.

Calling vkMapMemory is equivalent to calling vkMapMemory2KHR with an empty pNext chain.