Inside Macintosh: Open Transport /

Chapter 16 - Serial Endpoint Providers / Serial Endpoint Providers Reference

Serial-Specific Commands

I_SetSerialXOffState

This command sets the XOFF state of the serial port. Setting XOFF is equivalent to receiving an XOFF character, and clearing XOFF is equivalent to receiving an XON character. A value of kOTSerialForceXOffFalse unconditionally clears the XOFF state, while a value of kOTSerialForceXOffTrue unconditionally sets it. The following line of code unconditionally sets the XOFF state:

OTIoctl(theSerialEndpoint, I_SetSerialXOffState, kOTSerialForceXOffTrue);

Setting the XOFF state is equivalent to using a serial driver control call with a csCode value of 21, and clearing the XOFF state is equivalent to using a csCode value of 22.