---
title: vfs_devblocksize
framework: Kernel
role: symbol
role_heading: Function
platforms: [macOS 10.4+]
path: kernel/1523172-vfs_devblocksize
---

# vfs_devblocksize

Get the block size of the device underlying a mount.

## Declaration

```occ
int vfs_devblocksize(mount_t mp);
```

## Parameters

- `mp`: Mount for which to get block size.

## Return Value

Return Value Block size.