BBC BASIC Programmers' Reference

by Richard Russell, October 2013

The code below allows you to query the DNS to find the IP address(es) corresponding to a specified URL:

      SYS "LoadLibrary", "dnsapi.dll" TO dnsapi%
      SYS "GetProcAddress", dnsapi%, "DnsQuery_A" TO `DnsQuery`
      SYS "GetProcAddress", dnsapi%, "DnsRecordListFree" TO `DnsRecordListFree`

      DIM dnsr{pNext%, pName%, wType{l&,h&}, wDataLength{l&,h&}, dwFlags%, \
      \        dwTtl%, dwReserved%, dwData%}

      query$ = "www.google.com"

      SYS `DnsQuery`, query$, 1, 1, 0, dnsr{}, 0

      rr% = dnsr.pNext%

      WHILE dnsr.pNext%
        !(^dnsr{}+4) = dnsr.pNext%
        PRINT $$dnsr.pName% " ", FNipaddr$(dnsr.dwData%)
      ENDWHILE

      SYS `DnsRecordListFree`, rr%, 0

      SYS "FreeLibrary", dnsapi%

      PRINT "done"

      END

      DEF FNipaddr$(addr%)
      = STR$(addr% AND 255) + "." + STR$(addr% >>> 8 AND 255) + "." + \
      \ STR$(addr% >>> 16 AND 255) + "." + STR$(addr% >>> 24 AND 255)