---
title: "mxSignpostAnimationIntervalBegin(dso:log:name:signpostID:_:_:)"
framework: metrickit
role: symbol
role_heading: Function
path: "metrickit/mxsignpostanimationintervalbegin(dso:log:name:signpostid:_:_:)"
---

# mxSignpostAnimationIntervalBegin(dso:log:name:signpostID:_:_:)

Posts the start time of an animation interval to the log system.

## Declaration

```swift
func mxSignpostAnimationIntervalBegin(dso: UnsafeRawPointer = #dsohandle, log: OSLog, name: StaticString, signpostID: OSSignpostID = .exclusive, _ format: StaticString = "isAnimation=YES \n%{public, signpost:metrics}@", _ arguments: [any CVarArg] = [Unmanaged<NSObject>.fromOpaque(_MXSignpostMetricsSnapshot()).takeUnretainedValue()])
```

## Parameters

- `dso`: A parameter for internal system use.
- `log`: A log object to log the signpost to.
- `name`: A string containing the developer-assigned name of the custom event.
- `signpostID`: A parameter for internal system use.
- `format`: A parameter for internal system use.
- `arguments`: An array of arguments with a format string, followed by the expected number of arguments in the order that they appear in the string.

## Discussion

Discussion Call this function to mark the beginning of an animation interval in the metric kit log. Provide a log that you create with makeLogHandle(category:), a name for the event, and variable arguments for os_signpost_event_emit. Don’t alter the parameters dso, signpostID, or format.

## See Also

### Signpost and custom metrics

- [SignpostIntervalMetric](metrickit/signpostintervalmetric.md)
- [mxSignpost(_:dso:log:name:signpostID:_:_:)](metrickit/mxsignpost(_:dso:log:name:signpostid:_:_:).md)