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Example 6: Clearing All Flags

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This example demonstrates two different ways to clear all flags set in the registry and for the session:

  • Subtract the current flag value.

  • Subtract high values.

Note   The methods demonstrated by this example clear flags only. They do not reset the maximum stack trace size or kernel special pool tag to the default values.

Subtract the Current Flag Value

The following command clears all flags set in the system-wide flag entry in the registry by subtracting the current value of the entry. In this example, the current value is 0xE0. The command uses the /r parameter to indicate the system-wide registry mode and the E0 value with a minus sign (-) to subtract E0 from the flag value.

gflags /r -E0

In response, GFlags displays the revised value of system-wide flag registry entry. A value of zero indicates that the command is successful and that there are no longer any system-wide flags set in the registry.

Current Boot Registry Settings are: 00000000

Note that the following commands have the same effect as the command used in this example and can be used interchangeably:

gflags /r -20 -40 -80 
gflags /r -hfc -hpc -hvc

Subtract High Values

The following command clears all system-wide flags by subtracting high values (0xFFFFFFFF) from the system-wide flag setting.

gflags /r -ffffffff

In response, GFlags displays the revised value of the system-wide flag entry. A value of zero indicates that the command is successful and that there are no longer any system-wide flags set in the registry.

Current Boot Registry Settings are: 00000000

Tip   Type this command into Notepad, then save the file as clearflag.bat. Thereafter, to clear all flags, just type ClearFlag.

Finally, the following example demonstrates that the intuitive method of clearing all flags does not work.

The following command appears to set the value of the system-wide flag entry to 0. However, it actually adds zero to the system-wide flag value. In this example, the current value of the system-wide flag entry is 0xE0.

gflags /r 0

In response, GFlags displays the system-wide flag value after the command completes:

Current Boot Registry Settings are: 000000e0
    hfc - Enable heap free checking
    hpc - Enable heap parameter checking
    hvc - Enable heap validation on call

The command has no effect because it adds the value 0 to system-wide flag entry.