Description

This function is used to attach a servicelabel callback handler function. By default the mDNS sub-system provides a callback handler which attempts to acquire a unique label via monotonically increasing a suffix appended to the current label value, and then automatically attempting to claim the amended <label>.<service>.<proto>.local name.

	Note
	This function is not available if the system is configured with CYGFUN_MDNS_COMMON_NAME enabled.

The application can over-ride this default behaviour by registering an alternative handler function using this API. If the passed fn is NULL then the code reverts to the default mDNS callback handler.

The same limitations for the callback handler apply as for the hostname callback interface as documented by cyg_mdns_hostname_callback_register.