---
title: "completeIO(for:offset:length:status:flags:operationID:replyHandler:)"
framework: fskit
role: symbol
role_heading: Instance Method
path: "fskit/fsvolumekerneloffloadediooperations/completeio(for:offset:length:status:flags:operationid:replyhandler:)"
---

# completeIO(for:offset:length:status:flags:operationID:replyHandler:)

Completes an I/O operation for a given file.

## Declaration

```swift
func completeIO(for file: FSItem, offset: off_t, length: Int, status: any Error, flags: FSCompleteIOFlags, operationID: FSOperationID, replyHandler reply: @escaping @Sendable ((any Error)?) -> Void)
```

```swift
func completeIO(for file: FSItem, offset: off_t, length: Int, status: any Error, flags: FSCompleteIOFlags, operationID: FSOperationID) async throws
```

## Parameters

- `file`: The file for which the I/O operation completed.
- `offset`: The starting logical offset at which I/O started.
- `length`: The length of the I/O range (in bytes).
- `status`: Any error that occurred during the operation. If no error occurred, this parameter is nil.
- `flags`: Flags that affect the behavior of the complete I/O operation.
- `operationID`: A unique identifier of the blockmap call. Any value other than 0 (Objective-C) or doc://FSKit/documentation/FSKit/FSOperationID/unspecified (Swift) corresponds to a previous call to doc://FSKit/documentation/FSKit/FSVolumeKernelOffloadedIOOperations/blockmapFile(_:offset:length:flags:operationID:packer:replyHandler:) with the same operationID.
- `reply`: A block or closure to indicate success or failure. If completing I/O fails, pass an error as the one parameter to the reply handler. If completing I/O succeeds, pass nil. For an async Swift implementation, there’s no reply handler; simply throw an error or return normally.

## Discussion

Discussion Implement this method by updating a file’s metadata, such as its size and modification time. FSKit may call this method without an earlier call to blockmapFile(_:offset:length:flags:operationID:packer:replyHandler:). In this case, the operationID is 0 (Objective-C) or unspecified (Swift).