Types of socket activity that can cause the callback function of a CFSocket object to be called.
SDKs
Framework
struct CFSocketCallBackType
The callback types for which a callback is made is determined when the CFSocket object is created, such as with CFSocket, or later with CFSocket and CFSocket.
The k, k, and k callbacks are mutually exclusive.
k is available in macOS 10.2 and later.
static var readThe callback is called when data is available to be read or a new connection is waiting to be accepted. The data is not automatically read; the callback must read the data itself.
static var acceptNew connections will be automatically accepted and the callback is called with the data argument being a pointer to a CFSocket of the child socket. This callback is usable only with listening sockets.
static var dataIncoming data will be read in chunks in the background and the callback is called with the data argument being a CFData object containing the read data.
static var writeThe callback is called when the socket is writable. This callback type may be useful when large amounts of data are being sent rapidly over the socket and you want a notification when there is space in the kernel buffers for more data.