Starts resolution for a host object.


func CFHostStartInfoResolution(_ theHost: CFHost, _ info: CFHostInfoType, _ error: UnsafeMutablePointer<CFStreamError>?) -> Bool



The host, obtained by previously calling CFHostCreateCopy(_:_:), CFHostCreateWithAddress(_:_:), or CFHostCreateWithName(_:_:), that is to be resolved. This value must not be NULL.


A value of type CFHostInfoType specifying the type of information that is to be retrieved. See CFHostInfoType for possible values.


A pointer to a CFStreamError structure, that, if an error occurs, is set to the error and the error’s domain. In synchronous mode, the error indicates why resolution failed, and in asynchronous mode, the error indicates why resolution failed to start.

Return Value

TRUE if the resolution was started (asynchronous mode); FALSE if another resolution is already in progress for theHost or if an error occurred.


This function retrieves the information specified by info and stores it in the host.

In synchronous mode, this function blocks until the resolution has completed, in which case this function returns TRUE, until the resolution is stopped by calling CFHostCancelInfoResolution(_:_:) from another thread, in which case this function returns FALSE, or until an error occurs.

Special Considerations

This function is thread safe.

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.