Sets the maximum time that may be spent evaluating a single #If expression.
The timeout value to apply globally, in milliseconds.
A timeout is implemented to prevent long-running expressions from stalling keyboard input processing. If the timeout value is exceeded, the expression continues to evaluate, but the keyboard hook continues as if the expression had already returned false.
If this directive is unspecified in the script, it will behave as though set to 1000.
Note that the system implements its own timeout, defined by the DWORD value LowLevelHooksTimeout in the following registry key:
If the system timeout value is exceeded, the system may stop calling the script's keyboard hook, thereby preventing hook hotkeys from working until the hook is re-registered or the script is reloaded. The hook can usually be re-registered by suspending and un-suspending all hotkeys.
Microsoft's documentation is unclear about the details of this timeout, but research indicates the following for Windows 7 and later: If LowLevelHooksTimeout is not defined, the default timeout is 300ms. The hook may time out up to 10 times, but is silently removed if it times out an 11th time.
If a given hotkey has multiple #If variants, the timeout might be applied to each variant independently, making it more likely that the system timeout will be exceeded. This may be changed in a future update.
#IfTimeout 10 ; Set the timeout to 10 ms.