# vmnet_write(_:_:_:) Attempts to write specified packets to an interface. ``` func vmnet_write(_ interface: interface_ref, _ packets: UnsafeMutablePointer, _ pktcnt: UnsafeMutablePointer) -> vmnet_return_t ``` ## Parameters `interface` The interface reference. `packets` An array of packets to be written. `pktcnt` The number of packets to write. On return, this parameter is populated with the number of packets the framework wrote. ## Return Value `vmnet` on success, or an error code on failure. See `vmnet` for possible values. ## Discussion None of the packet to be written should exceed the size of the value of [`vmnet_max_packet_size_key`](/documentation/vmnet/vmnet_max_packet_size_key) for the interface. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)