# sec_protocol_metadata_copy_negotiated_protocol(_:) ``` func sec_protocol_metadata_copy_negotiated_protocol(_ metadata: sec_protocol_metadata_t) -> UnsafePointer? ``` ## Parameters `metadata` A `sec_protocol_metadata_t` instance. ## Return Value A NULL-terminated string carrying the negotiated protocol. ## Discussion \abstract Copy the application protocol negotiated, e.g., via the TLS ALPN extension. The caller is expected to `free` the output string when no longer needed. --- 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)