When the IsOS function is given OS_DOMAINMEMBER as its dwOS argument, it answers according to whether the NETAPI32 function NetGetJoinInformation reports that the local computer is joined to a domain.

The answer is sought only when the function is first called for this case of dwOS. Version 6.1 and higher return TRUE if a call to NetGetJoinInformation for the local computer produces NetSetupDomainName as the join status.

Version 6.0 links to the NetGetJoinInformation function dynamically. It does not expect the function to be available if the operating system is too old. It first checks that the platform is NT and the major version ≥ 5 (as for OS_WIN2000ORGREATER), and only then proceeds to testing the join status.


The OS_DOMAINMEMBER case of the SHLWAPI function IsOS is supported in version 6.0 and higher.