 valid. <a class="el" href="group__netdbapi.html#ga39746b4b096060ca3e8c6ee7a7560b1d">gethostbyname()</a> then does a dns_lookup() to see if the name is already in the table. If so, the IP is returned. If not, a query is issued and the function returns with a ERR_INPROGRESS status. The app using the dns client must then go into a waiting state.</p>
<p>Once a hostname has been resolved (or found to be non-existent), the resolver code calls a specified callback function (which must be implemented by the module