怎么获得guid

如何获得guid？
oleObject PBObject 
long ll_result
string s_guid

PBObject = CREATE oleObject

ll_result = PBObject.ConnectToNewObject("PowerBuilder.Application")
IF ll_result < 0 THEN
messagebox("","连接失败：与PowerBuilder.Application连接出错！")
return
ELSE
ll_result = PBObject.GenerateGUID(s_guid)
END IF

IF ll_result < 0 THEN
messagebox("","生成GUID失败：不能获得GUID！")
return
END IF

s_guid = mid(s_guid,2,len(s_guid) - 2)


网上很多地方有这段代码取guid，pb80，pbvm80.dll ，rpcrt4.dll, pbaen80.tld文件都有
为何还是取不到guid的值？

------解决方案--------------------
ll_result = PBObject.GenerateGUID(ref s_guid)