Error notification to application from io-char

Hi All,
In QNX documentation, it is stated that interrupt is received whenever an error like parity error, framing error occurs.
Serial Driver passes the error codes to io-char using tti() function call.
How does the application get notified about this error ?
Does io-char set the return value of the read() call to these error codes ?
Or does the io-char send the error messages in the receive buffer which is read by the application ?