Today I was wondering why the GFlags option Stop on hung GUI appears in the Kernel Flags tab of the GFlags user interface. Does the kernel have a GUI which could hang?
So I tried to get some information from Microsoft, but MSDN just says:
The Stop on hung GUI flag appears in GFlags, but it has no effect on Windows.
So I wonder even more: a kernel flag for a kernel which has a GUI, but it's not the Windows kernel?
Although it seems not of practical use, can anyone explain this?
I also tried to get more information from WinDbg .hh !gflag
, but it doesn't even give the statement that this won't work on Windows.
Kernel flag
indicates flag takes effect immediatelywithout requiring a reboot
Registry flag requires a reboot
for the flags to take effectthe kernel does not have any gui that could hang.
the term windows doesnt mean kernel but the gui windows of the running application
check NtSetSystemInformation in your os to understand why 0x8 does not take effect
basically there are a few hardcoded magic numbers inside this api which tests each request for GlobalFlag changes and allows them or disallows them in xp-sp3 this magic value is
0B2319BF0
so any flag that is < 0x10 will be disallowed and stop on hung gui is 0x8 so it isnt effective and you cant set this from registry tabso effectively no way of setting this flag