## Input/Output Device Driver Reference

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### State of the COM Port

The following IOCtls can be used to determine the state of the COM port or if a given event happened. However, the exact timing relationship between this information and the specific data being received or transmitted at the time of the event is not available.

Query COM Event Information (ASYNC_GETCOMMEVENT)
Query COM Status (ASYNC_GETCOMMSTATUS)
Query COM Error (ASYNC_GETCOMMERROR)