When the IsOS function is given OS_WOW6432 as its dwOS argument, it tells whether the current process is a 32-bit process running on 64-bit Windows.


The answer is TRUE if a call to the NTDLL function NtQueryInformationProcess for the current process produces a non-zero dword of data for the information class ProcessWow64Information.


Version 6.0 links to the NtQueryInformationProcess function dynamically and seeks the process information only when the IsOS function is first called for this case of dwOS.


The OS_WOW6432 case of the SHLWAPI function IsOS is supported in version 6.0 and higher.