What's this (undocumented?) call to GetFileAttributesW()? - winapi

Question

When I open WinBase.inl, I see:
ISOLATION_AWARE_INLINE FARPROC IsolationAwarePrivatenCv
IsolationAwarePrivatezltRgCebPnQQeRff(
__in IsolationAwarePrivateCpBAFGnAG_zBqHyr_vAsB c,
__inout IsolationAwarePrivateCzHGnoyr_zBqHyr_vAsB m,
__in PCSTR ProcName
)
{
FARPROC Proc = NULL;
HMODULE hModule;
#ifdef _M_IX86
static HMODULE s_moduleUnicows;
static BOOL s_fUnicowsInitialized;
/*
get unicows.dll loaded on-demand
*/
if (!s_fUnicowsInitialized)
{
if ((GetVersion() & 0x80000000) != 0)
{
GetFileAttributesW(L"???.???");
s_moduleUnicows = GetModuleHandleA("Unicows.dll");
}
s_fUnicowsInitialized = TRUE;
}
/*
always call GetProcAddress(unicows) before the usual .dll
*/
if (s_moduleUnicows != NULL)
{
Proc = GetProcAddress(s_moduleUnicows, ProcName);
if (Proc != NULL)
goto Exit;
}
#endif
hModule = m->WinbaseIsolationAwarePrivateybNQRQzbQhYR;
if (hModule == NULL)
{
#ifdef _M_IX86
hModule = (((GetVersion() & 0x80000000) != 0) ? (*c->WinbaseIsolationAwarePrivateybNQn)(c->WinbaseIsolationAwarePrivateANZRn) : (*c->WinbaseIsolationAwarePrivateybNQJ)(c->WinbaseIsolationAwarePrivateANZRJ));
#else
hModule = (*c->WinbaseIsolationAwarePrivateybNQJ)(c->WinbaseIsolationAwarePrivateANZRJ);
#endif
if (hModule == NULL)
goto Exit;
m->WinbaseIsolationAwarePrivateybNQRQzbQhYR = hModule;
}
Proc = GetProcAddress(hModule, ProcName);
Exit:
return Proc;
}
Does anyone know what GetFileAttributesW(L"???.???"); does?

Answer 1

It's sort of not doing anything. It's a dummy call with the sole purpose of forcing the DLL it lives in (Unicows.dll) to be loaded into memory so its handle can be retrieved. The parameter is just a useless Unicode string "filename", since the actual value isn't wanted and it's a little faster if the call errors out on an illegal filename (no wildcards allowed) rather than hitting the disk just to throw the result out.