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

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

Posts a single custom metric, the start time of a custom metric, or the end time of a custom metric to the log system.

## Declaration

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

## Parameters

- `type`: A value that represents the type of the signpost: event: A single custom metric. begin: The start time of a custom metric. end: The end time of a custom metric.
- `dso`: A parameter for internal system use.
- `log`: A log for the category of the event that was created previously using doc://com.apple.metrickit/documentation/MetricKit/MXMetricManager/makeLogHandle(category:).
- `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`: The variable arguments for doc://com.apple.documentation/documentation/os/os_signpost_event_emit.

## Mentioned in

Monitoring app performance with MetricKit

## Discussion

Discussion Call this function to mark a custom metric, custom metric start time, or custom metric end time in the metric kit log. Provide a log that you create with makeLogHandle(category:), the type of the event, 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)
- [mxSignpostAnimationIntervalBegin(dso:log:name:signpostID:_:_:)](metrickit/mxsignpostanimationintervalbegin(dso:log:name:signpostid:_:_:).md)