---
title: mbuf_trailingspace
framework: Kernel
role: symbol
role_heading: Function
platforms: [macOS 10.4+]
path: kernel/1535759-mbuf_trailingspace
---

# mbuf_trailingspace

## Declaration

```occ
size_t mbuf_trailingspace(const mbuf_t mbuf);
```

## Parameters

- `mbuf`: The mbuf.

## Return Value

Return Value The number of unused bytes following the current data.

## Discussion

Discussion Determines the space available in the mbuf following the current data.