ASYNC SETBREAKON

This function sets break on.

Category

IOCTL_ASYNC (01h)

Function

ASYNC_SETBREAKON (4Bh)

Parameter Packet Format

None. Packet pointer must be NULL.

Data Packet Format

┌───────────────────────────────────────────────────┐
│Field                       Length     C Datatype  │
├───────────────────────────────────────────────────┤
│COM Error Word (COMERR)     WORD       USHORT      │
└───────────────────────────────────────────────────┘

Returns

If the call is made with an invalid Parameter Packet pointer and a general failure error is reported, this function is not performed and valid information is not returned in the Data Packet.

Remarks

If a general failure error is not returned, the physical device driver generates the break signal immediately. It is not considered an error if the physical device driver is already generating a break signal. The device driver does not wait for the transmit hardware to become empty. Note that more data is not given to the transmit hardware until the break is turned off. The break signal is always transmitted, regardless of whether or not the physical device driver is transmitting characters for other reasons.