ungui web应用在 ISAPI modules模式下如何获取DLL所在的路径？

When I deploy my ungui webapp as  ISAPI modules(under Apache 2.2 as DLL files),I use Delphi function getdir to get the path info where my Webapp dll exists in,but  getdir returns Apache home path.How can I get the path info where my Webapp DLLs exists in?

thank you very much.

wxb_km,1/9
使用函数：
ExtractFileDir(ExpandFileName(GetModuleName(HInstance)))