---
title: ctl_enqueuembuf
framework: Kernel
role: symbol
role_heading: Function
platforms: [macOS 10.13+]
path: kernel/1809171-ctl_enqueuembuf
---

# ctl_enqueuembuf

## Declaration

```occ
errno_t ctl_enqueuembuf(kern_ctl_ref kctlref, u_int32_t unit, mbuf_t m, u_int32_t flags);
```

## Parameters

- `kctlref`: The control reference of the kernel control.
- `unit`: The unit number of the kernel control instance.
- `m`: An mbuf chain containing the data to send to the client.
- `flags`: Send flags. CTL_DATA_NOWAKEUP and CTL_DATA_EOR are currently the only supported flags.

## Return Value

Return Value 0 - Data was enqueued to be read by the client. EINVAL - Invalid parameters. ENOBUFS - The queue is full.

## Discussion

Discussion Send data stored in an mbuf chain from the kernel control to the client. The caller is responsible for freeing the mbuf chain if ctl_enqueuembuf returns an error.

## See Also

### control

- [ctl_deregister](kernel/1809161-ctl_deregister.md)
- [ctl_enqueuedata](kernel/1809168-ctl_enqueuedata.md)
- [ctl_getenqueuereadable](kernel/2919907-ctl_getenqueuereadable.md)
- [ctl_getenqueuespace](kernel/1809173-ctl_getenqueuespace.md)
- [ctl_register](kernel/1809176-ctl_register.md)