ASYNC_GETLINESTATUS
Returns the transmit data status.
- Category
- IOCTL_ASYNC (01h)
- Function
- ASYNC_GETLINESTATUS (65h)
Parameter Packet Format
None. Packet pointer must be NULL.
Data Packet Format
| Field | Length | C Datatype |
|---|---|---|
| Transmit Status | BYTE | UCHAR |
- Transmit Status
- Returned as bit-significant values. If the bit is 1, the condition is TRUE. If the bit is 0, the condition is FALSE. The number at the beginning of the description is the bit position number. The bit positions go from least to most significant.
- Bit 0: WRITE request packets in progress or queued
- Bit 1: Data in the physical device driver transmit queue
- Bit 2: Transmit hardware is currently transmitting data
- Bit 3: Character waiting to be transmitted immediately
- Bit 4: Waiting to automatically transmit an XON
- Bit 5: Waiting to automatically transmit an XOFF
- Bit 6: Undefined
- Bit 7: Undefined
Returns
If the call is made with an invalid Parameter Packet value, a general failure error is reported and valid information is not returned in the Data Packet.
Remarks
If a general failure error is not returned, the physical device driver returns the current transmit status of the COM device.