ATTR_ALLOW_UNSAFE_TIMER_EVENTS
- Updated2023-02-21
- 2 minute(s) read
ATTR_ALLOW_UNSAFE_TIMER_EVENTS
| Type: | System attribute |
| Description: | By default, timer control callbacks do not occur while you are moving or sizing a window, while the system menu is pulled down, or while the Alt-Tab key is pressed. (These are called "event-blocking conditions.") You can use this attribute to enable timer events under some, but not all, of the event-blocking conditions. If you set this attribute to TRUE, timer events are blocked only under the following conditions: (1) You have clicked on a window title bar, you are holding the mouse button down, but you are not moving the mouse. (2) You are moving or resizing a window, and the Windows "Show Window Contents While Dragging" option is disabled. There are several limitations to this feature. One limitation is that while an event-blocking condition is in effect, timer callbacks are called no faster than once per 55 milliseconds. Another limitation is that if a timer callback is called during an event-blocking condition and the callback causes events to be processed, mouse and keyboard input can behave erratically. Your program can cause this to happen in the following ways. (1) The timer callback function calls ProcessSystemEvents in a loop. (2) The timer callback function calls RunUserInterface, GetUserEvent, or a popup panel function such as MessagePopup or FileSelectPopup. (3) Program execution is suspended in the timer callback function because of a breakpoint or run-time error. In either case, the system functions normally once the timer callback returns. This problem is inherent to Windows and occurs regardless of the development environment. You should not enable this attribute until the code in your timer callbacks has been thoroughly debugged. The behavior of the system is undefined if you hit a breakpoint or run-time error when an event-blocking condition is in effect. 0 = Do not allow unsafe timer events. 1 = Allow unsafe timer events. |
| Data Type: | integer |
| Default Value: | 0 |
| LabWindows/CVI Compatibility: |
LabWindows/CVI 4.0 and later |
Values
| 0 | False |
| 1 | True |