---
title: "init(upstream:prefix:to:)"
framework: combine
role: symbol
role_heading: Initializer
path: "combine/publishers/print/init(upstream:prefix:to:)"
---

# init(upstream:prefix:to:)

Creates a publisher that prints log messages for all publishing events.

## Declaration

```swift
init(upstream: Upstream, prefix: String, to stream: (any TextOutputStream)? = nil)
```

## Parameters

- `upstream`: The publisher from which this publisher receives elements.
- `prefix`: A string with which to prefix all log messages.