Unexpected RegNotifyChangeKeyValue() Behaviour - windows

Question

RegNotifyChangeKeyValue()
function can provide alerts to changes in the security of a registry key.
I, possibly mistakenly, expected it to alert the caller if the permissions
of the user calling RegNotifyChangeKeyValue() were changed to deny the
user read permission.
From testing it does not inform the caller of this change, nor does it
inform the user of any subsequent changes to the key nor does it fail
in anyway: the caller is completely unaware that it is no longer being
informed of any change.
Code (stackc.c):
#include <windows.h>
#include <stdio.h>
int main()
{
HKEY h_key;
HANDLE h_event;
DWORD last_error = RegCreateKeyEx(HKEY_LOCAL_MACHINE,
"Software\\stackoverflow-testing-key",
0,
0,
REG_OPTION_NON_VOLATILE,
KEY_READ,
0,
&h_key,
0);
if (ERROR_SUCCESS != last_error)
{
fprintf(stderr, "Failed to create key: %d\n", last_error);
exit(1);
}
RegCloseKey(h_key);
last_error = RegOpenKeyEx(HKEY_LOCAL_MACHINE,
"Software\\stackoverflow-testing-key",
0,
KEY_NOTIFY,
&h_key);
if (ERROR_SUCCESS != last_error)
{
fprintf(stderr, "Failed to open key: %d\n", last_error);
exit(1);
}
h_event = CreateEvent(0, FALSE, FALSE, 0);
if (h_event)
{
int change_count = 0;
while (change_count < 2)
{
DWORD wait_status;
last_error = RegNotifyChangeKeyValue(
h_key,
FALSE,
REG_NOTIFY_CHANGE_NAME |
REG_NOTIFY_CHANGE_ATTRIBUTES |
REG_NOTIFY_CHANGE_LAST_SET |
REG_NOTIFY_CHANGE_SECURITY,
h_event,
TRUE);
if (ERROR_SUCCESS != last_error)
{
fprintf(stderr, "Failed to notify: %d\n", last_error);
break;
}
wait_status = WaitForSingleObject(h_event, INFINITE);
if (WAIT_FAILED == wait_status)
{
fprintf(stderr, "Wait failed: %d\n", GetLastError());
break;
}
if (WAIT_OBJECT_0 == wait_status)
{
printf("Registry key changed!\n");
change_count++;
}
}
CloseHandle(h_event);
}
RegCloseKey(h_key);
RegDeleteKey(HKEY_LOCAL_MACHINE, "Software\\stackoverflow-testing-key");
return 0;
}
Build commands:
cl.exe -nologo -c -DWIN32 -Zi -MT -W4 -Ox stackc.c -Fo./stackc.obj
link.exe -NOLOGO -INCREMENTAL:NO -OUT:stackc.exe stackc.obj Kernel32.lib advapi32.lib
I am running Windows XP Service Pack3 x86.
To test I executed stackc.exe and ran the Registry editor
(Start->Run "regedit.exe"), browsed to
HKEY_LOCAL_MACHINE\Software\stackoverflow-testing-key
and right-clicked and selected Permissions, selected the user
which I was executing stackc.exe as and denied read permission.
I then added a value to the key and stackc.exe is never notified.
Can someone provide an explanation for this behaviour or, preferably,
point to an error in the posted code?