C-library consists of asynchronous DNS resolver

Need to find a asynchronous DNS resolver implemented in C (except Sofia Resolver) which supports DNS queries for NAPTR, SRV and A records. It would be desired to support internal caching. Any suggestions/recommendations? 开发者_运维百科Currently looking at ldns which supports NAPTR, SVC and A queries. But, If I have understood correctly, it is not asynch DNS resolver.

c-ares, which is used within libCurl, is an asynchronous resolver.

have you tried libunboud? Not sure about NAPTR

http://www.unbound.net/index.html