---
title: OSLogMessageComponent
framework: OSLog
role: symbol
role_heading: Class
platforms: [iOS 15.0+, iPadOS 15.0+, Mac Catalyst 15.0+, macOS 10.15+, tvOS 15.0+, visionOS 1.0+, watchOS 8.0+]
path: oslog/oslogmessagecomponent
---

# OSLogMessageComponent

The message arguments for a particular entry.

## Declaration

```swift
class OSLogMessageComponent
```

## Overview

Overview There is one component for each placeholder in the formatString plus one component for any text after the last placeholder.

## Topics

### Reading the Argument

- [argument](oslog/oslogmessagecomponent/argument-swift.property.md)
- [OSLogMessageComponent.Argument](oslog/oslogmessagecomponent/argument-swift.enum.md)
- [argumentCategory](oslog/oslogmessagecomponent/argumentcategory-swift.property.md)
- [OSLogMessageComponent.ArgumentCategory](oslog/oslogmessagecomponent/argumentcategory-swift.enum.md)

### Reading the Message Component

- [formatSubstring](oslog/oslogmessagecomponent/formatsubstring.md)
- [placeholder](oslog/oslogmessagecomponent/placeholder.md)

### Accessing the Argument

- [argumentDataValue](oslog/oslogmessagecomponent/argumentdatavalue.md)
- [argumentDoubleValue](oslog/oslogmessagecomponent/argumentdoublevalue.md)
- [argumentInt64Value](oslog/oslogmessagecomponent/argumentint64value.md)
- [argumentNumberValue](oslog/oslogmessagecomponent/argumentnumbervalue.md)
- [argumentStringValue](oslog/oslogmessagecomponent/argumentstringvalue.md)
- [argumentUInt64Value](oslog/oslogmessagecomponent/argumentuint64value.md)

## Relationships

### Inherits From

- [NSObject](objectivec/nsobject-swift.class.md)

### Conforms To

- [CVarArg](swift/cvararg.md)
- [CustomDebugStringConvertible](swift/customdebugstringconvertible.md)
- [CustomStringConvertible](swift/customstringconvertible.md)
- [Equatable](swift/equatable.md)
- [Hashable](swift/hashable.md)
- [NSCoding](foundation/nscoding.md)
- [NSObjectProtocol](objectivec/nsobjectprotocol.md)
- [NSSecureCoding](foundation/nssecurecoding.md)

## See Also

### Entry Data

- [OSLogPosition](oslog/oslogposition.md)