# xpc_connection_set_peer_entitlement_exists_requirement(_:_:) Sets a requirement that the executable for the peer process has a valid code signature that contains an entitlement. ``` func xpc_connection_set_peer_entitlement_exists_requirement(_ connection: xpc_connection_t, _ entitlement: UnsafePointer) -> Int32 ``` ## Parameters `connection` The XPC connection. `entitlement` The name of the entitlement to check. ## Return Value On success, `0`. Otherwise, a value from [Errors](/documentation/XPC/xpc-connections#Errors). ## Discussion When you set this requirement on a connection, the operating system checks that peer process satisfies the requirement every time it sends a message to your process. If the peer process initiated the connection and its executable doesn’t have the requested entitlement, then you don’t receive a message and the operating system doesn’t call your event handler. If your process sent a message to its peer expecting a reply, and its executable doesn’t have the requested entitlement, then you don’t receive a reply and the operating system delivers [`XPC_ERROR_PEER_CODE_SIGNING_REQUIREMENT`](/documentation/XPC/XPC_ERROR_PEER_CODE_SIGNING_REQUIREMENT-c.macro) instead. > Important: > It’s an error to call this function multiple times for the same connection, or to call multiple functions that set code-signing requirements on the same connection. If you do, then the operating system terminates your process. --- 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)