When calling Win32 Api, the error and the reason are written in System Error Codes. You can use the error code to determine the cause of the error when you encounter an error.
The reason for the additional label ERROR_IO_PENDING is that when the error is returned, it does not mean that the function call failed. It is that the current timer queue is busy and cannot be processed immediately. However, it has been successfully submitted and will be processed when the subsequent timer queue is free.
Other possible errors were not submitted successfully. So they were not successfully deleted from the timer queue, and the timer will not be deleted in the future, so it is recommended that you try to call the function again.
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