Flushes all input or output queues.
The I_FLUSH operation flushes all input or output queues, depending on the value of the arg parameter. Legal values for the arg parameter are:
| Value | Description | 
|---|---|
| FLUSHR | Flush read queues. | 
| FLUSHW | Flush write queues. | 
| FLUSHRW | Flush read and write queues. | 
This operation is part of STREAMS Kernel Extensions.
If unsuccessful, the errno global variable is set to one of the following values:
| Value | Description | 
|---|---|
| ENOSR | Unable to allocate buffers for flush message due to insufficient STREAMS memory resources. | 
| EINVAL | Invalid value for the arg parameter. | 
| ENXIO | Hangup received on the fildes parameter. |