Geoff Chappell - Software Analyst
This function tests the value of a Windows Shell restriction and displays a message box if the restriction applies.
BOOL SHIsRestricted ( HWND hwnd, RESTRICTIONS rest);
The hWnd argument provides a handle to the window that should own the message box, or is NULL.
The rest argument selects the restriction whose value is wanted. The supported values in the RESTRICTIONS enumeration are listed separately.
The function returns TRUE if the selected restriction evaluates to anything other than zero. Otherwise, the function returns FALSE.
This function exists as a convenience for the case where a restriction is a boolean indicator of whether some Windows feature is restricted from use, typically as an administrative policy. The restriction is evaluated by calling the SHELL32 function SHRestricted (passing the rest arguments as given). If the feature turns out to be restricted, then the SHLWAPI function SHRestrictedMessageBox is called to alert the user.
The SHIsRestricted function is exported from SHDOCVW as ordinal 173 in version 5.0 and higher.
SHDOCVW version 6.1 retires this function: it continues to be exported but only as a forward to SHUNIMPL for certain failure.
Though this function dates from as long ago as 1999, it was still not documented by Microsoft as late as the January 2007 edition of the Windows Vista Software Development Kit (SDK).
There is a strong suggestion that this function is not used by any executables that are distributed as standard with either Windows XP Service Pack 1 or Windows Vista. It seems not even to be used within SHDOCVW, i.e., for internal calls.