This is the function:

DECLARE INTEGER GetAdaptersInfo IN iphlpapi;
STRING @ pAdapterInfo,;
LONG @ pOutBufLen

Returns adapter name, MAC address (Media Access Control), IP address and more.

MSDN link:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/iphlp/iphlp/getadaptersinfo.asp

Sample FoxPro code:
http://www.news2news.com/vfp?example=347&function=526