Gets reachability information from a host.


func CFHostGetReachability(_ theHost: CFHost, _ hasBeenResolved: UnsafeMutablePointer<DarwinBoolean>?) -> Unmanaged<CFData>?



The host whose reachability is to be obtained. The host must have been previously resolved. (To resolve a host, call CFHostStartInfoResolution(_:_:_:).) This value must not be NULL.


On return, contains TRUE if the reachability was available, otherwise FALSE. This value may be NULL.

Return Value

A CFData object that wraps the reachability flags (SCNetworkConnectionFlags) defined in SystemConfiguration/SCNetwork.h, or NULL if reachability information was not available.


This function gets reachability information in a thread-safe way, but the resulting data is not thread-safe. The data is returned as a “get” as opposed to a copy, so the data is not safe if the CFHost is altered from another thread.

See Also


class CFHost

An opaque reference representing an CFHost object.

enum CFHostInfoType

Values indicating the type of data that is to be resolved or the type of data that was resolved.

struct CFHostClientContext

A structure containing user-defined data and callbacks for CFHost objects.

func CFHostCreateWithAddress(CFAllocator?, CFData) -> Unmanaged<CFHost>

Uses an address to create an instance of a host object.

func CFHostCreateWithName(CFAllocator?, CFString) -> Unmanaged<CFHost>

Uses a name to create an instance of a host object.

func CFHostGetTypeID() -> CFTypeID

Gets the Core Foundation type identifier for the CFHost opaque type.

func CFHostSetClient(CFHost, CFHostClientCallBack?, UnsafeMutablePointer<CFHostClientContext>?) -> Bool

Associates a client context and a callback function with a CFHost object or disassociates a client context and callback function that were previously set.