---
title: "init(_:_:_:_:)"
framework: combine
role: symbol
role_heading: Initializer
path: "combine/publishers/merge4/init(_:_:_:_:)"
---

# init(_:_:_:_:)

Creates a publisher created by applying the merge function to four upstream publishers.

## Declaration

```swift
init(_ a: A, _ b: B, _ c: C, _ d: D)
```

## Parameters

- `a`: A publisher to merge
- `b`: A second publisher to merge.
- `c`: A third publisher to merge.
- `d`: A fourth publisher to merge.