Asynchronous Serial Communications Programmer's Reference Manual (32022-90052)

180 Chapter8

Intrinsics Reference

FCONTROL(23, 24)

Because parity requires the eighth bit to be set as a

parity bit, it is not possible to use parity with 8-bit

character sets. If binary mode is enabled, the parity bit

will be passed through as data, and no parity checking

will occur.

If enabling parity, make sure that your program also

requests the terminal operator to change the physical

parity setting of the terminal to the new setting of the

ASC software. Additionally, if a user wants the

terminal to check parity on incoming data, the local

terminal control used to turn parity checking on or off

should be set to ON.

If either of these FCONTROL calls is issued against a

terminal connected via PAD, DTC Telnet, Telnet/iX, or

VT (from a PC or HP-UX local client), the call will

return a CCE condition code but will actually have no

effect on the parity which the device is transmitting.

Additionally, the call will return a meaningless value in

param.

If a parity error is detected by the ASC software, the

current read is completed in error, and no read data is

returned. The ASC software reports the error to the

program reading the data.

Condition Codes

CCE Request granted.

CCG Not returned by this intrinsic.

CCL Request failed because the ﬁle number speciﬁed did not

belong to this process or the device is not a terminal.

Additional Discussion

See also discussion of FCONTROL(36) in this manual.