Geoff Chappell - Software Analyst
When the IsOS function is given OS_APPLIANCE as its dwOS argument, it answers according to the following registry value:
|Type||REG_DWORD or REG_BINARY|
The function returns TRUE or FALSE according to whether the value is non-zero or zero. Before version 6.1, the value is queried only when the function is first called for this case of dwOS, and data that does not have type REG_DWORD evaluates as zero.
The OS_APPLIANCE case of the SHLWAPI function IsOS is supported in builds of version 6.0 from Windows XP SP2, and higher.