---
title: proto_plumb_handler
framework: Kernel
role: symbol
role_heading: Type Alias
platforms: [macOS 10.4+]
path: kernel/proto_plumb_handler
---

# proto_plumb_handler

## Declaration

```occ
typedef errno_t (*proto_plumb_handler)(ifnet_t ifp, protocol_family_t protocol);
```

## Parameters

- `ifp`: The interface the protocol should be attached to.
- `protocol_family`: The protocol that should be attached to the interface.

## Return Value

Return Value A non-zero value of the attach failed.

## Discussion

Discussion proto_plumb_handler is called to attach a protocol to an interface. A typical protocol plumb function would fill out an ifnet_attach_proto_param and call ifnet_attach_protocol.