# resolveCounterHeap(_:range:buffer:fenceToWait:fenceToUpdate:) Encodes a command that resolves an opaque counter heap into a buffer. ``` func resolveCounterHeap(_ counterHeap: any MTL4CounterHeap, range: Range, buffer: MTL4BufferRange, fenceToWait: (any MTLFence)? = nil, fenceToUpdate: (any MTLFence)? = nil) ``` ## Parameters `counterHeap` A heap the command resolves. `range` A range of index values within the heap the command resolves. `buffer` A buffer the command saves the data it resolves into. `fenceToWait` A fence the GPU waits for before starting, if applicable; otherwise `nil`. `fenceToUpdate` A fence the system updates after the command finishes resolving the data; otherwise `nil`. ## Discussion The command this method encodes converts the data within a counter heap into a common format and stores it into the `buffer` parameter. The command places each entry in the counter heap within `range` sequentially, starting at `offset`. Each entry needs to be a fixed size that you can query by calling the [`size(ofCounterHeapEntry:)`](/documentation/Metal/MTLDevice/size(ofCounterHeapEntry:)) method. This command runs during the `MTLStageBlit` stage of the GPU timeline. Barrier against this stage to ensure the data is present in the resolve buffer parameter before you access it. > Note: Your app needs ensure the GPU places data in the heap before you resolve it by > synchronizing this stage with other GPU operations. Similarly, your app needs to synchronize any GPU accesses to `buffer` after the command completes with barrier. If your app needs to access `buffer` from the CPU, signal an [`MTLSharedEvent`](/documentation/Metal/MTLSharedEvent) to notify the CPU when it’s ready. Alternatively, you can resolve the heap’s data from the CPU by calling the heap’s [`resolveCounterRange:`](/documentation/Metal/MTL4CounterHeap/resolveCounterRange:) method. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)