# CFSocketCreate(_:_:_:_:_:_:_:) Creates a CFSocket object of a specified protocol and type. ``` func CFSocketCreate(_ allocator: CFAllocator!, _ protocolFamily: Int32, _ socketType: Int32, _ protocol: Int32, _ callBackTypes: CFOptionFlags, _ callout: CFSocketCallBack!, _ context: UnsafePointer!) -> CFSocket! ``` ## Parameters `allocator` The allocator to use to allocate memory for the new object. Pass `NULL` or [`kCFAllocatorDefault`](/documentation/CoreFoundation/kCFAllocatorDefault) to use the current default allocator. `protocolFamily` The protocol family for the socket. If negative or 0 is passed, the socket defaults to `PF_INET`. `socketType` The socket type to create. If `protocolFamily` is `PF_INET` and `socketType` is negative or 0, the socket type defaults to `SOCK_STREAM`. `protocol` The protocol for the socket. If `protocolFamily` is `PF_INET` and `protocol` is negative or 0, the socket protocol defaults to `IPPROTO_TCP` if `socketType` is `SOCK_STREAM` or `IPPROTO_UDP` if `socketType` is `SOCK_DGRAM`. `callBackTypes` A bitwise-OR combination of the types of socket activity that should cause `callout` to be called. See [`CFSocketCallBackType`](/documentation/CoreFoundation/CFSocketCallBackType) for the possible activity values. `callout` The function to call when one of the activities indicated by `callBackTypes` occurs. `context` A structure holding contextual information for the CFSocket object. The function copies the information out of the structure, so the memory pointed to by `context` does not need to persist beyond the function call. Can be `NULL`. ## Return Value The new CFSocket object, or `NULL` if an error occurred. Ownership follows the [The Create Rule](https://developer.apple.com/library/archive/documentation/CoreFoundation/Conceptual/CFMemoryMgmt/Concepts/Ownership.html#//apple_ref/doc/uid/20001148-103029). --- 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)