davis@pacific.mps.ohio-state.edu ("John E. Davis") (04/09/91)
Hi,
This is a BSD unix question. I to read a character in RAW mode from, say,
file descriptor 2. Raw turns off all input/output processing. However, I
only want input processing turned off. This is not the same as CBREAK.
CBREAK still does input processing on the special characters ^Z (stop),
^\ (quit), etc... which I want turned off. So my question is this: from
within a C program how do I accomplish the above objective?
Currently I have:
{ .
.
.
#define TTY_DESCR 2
extern int ioctl(int, int, ...);
#include <sgtty.h>
struct sgttyb OLDTTY;
.
.
void init_io()
{
struct sgttyb newtty;
ioctl(TTY_DESCR, TIOCGETP, &OLDTTY);
newtty = OLDTTY;
newtty.sg_flags |= CBREAK;
newtty.sg_flags &= ~(ECHO | XTABS);
ioctl(TTY_DESCR, TIOCSETP, &newtty);
}
Here I use CBREAK mode but I want to allow all input characters to pass
through unprocessed and I want output processing. What are the necessaary
changes? Note: I did RTFM but all it talked about was termio which our system
does not have (although for some stupid reason the man pages think so).
A related question (perhaps the same question): It seems that from the shell,
I can type `stty -isig' to turn off input processing on the interrupt
characters (^Z, etc..). In BSD, how do I accomplish this with an ioctl?
Thanks,
--
John
bitnet: davis@ohstpy
internet: davis@pacific.mps.ohio-state.edutorek@elf.ee.lbl.gov (Chris Torek) (04/09/91)
In article <DAVIS.91Apr9055635@pacific.mps.ohio-state.edu> davis@pacific.mps.ohio-state.edu (John E. Davis) writes: >I [want] to read [an arbitrary 8 bit data] character ... from, say, >file descriptor 2. Raw [mode would work except that it] turns off all >input/output processing. ... I only want input processing turned off. >from within a C program how do I accomplish the above objective? >A related question (perhaps the same question): It seems that from the shell, >I can type `stty -isig' to turn off input processing on the interrupt >characters (^Z, etc..). In BSD, how do I accomplish this with an ioctl? In BSD, you start by reading about termios. If you have `stty -isig' you have POSIX termios. In general, you want CS8 (8 data bits), optional parity, ISIG and ICANON turned off, and OPOST turned on. If you have a BSD system without `stty -isig' and without TIOCGETA etc., you can fake 8-bit input without disabling output processing by setting LLITIN in the `local mode word', CBREAK in the sgtty flags, and also turning off all the special characters (struct tchars, struct ltchars). -- In-Real-Life: Chris Torek, Lawrence Berkeley Lab CSE/EE (+1 415 486 5427) Berkeley, CA Domain: torek@ee.lbl.gov
guy@auspex.auspex.com (Guy Harris) (04/11/91)
In article <DAVIS.91Apr9055635@pacific.mps.ohio-state.edu> davis@pacific.mps.ohio-state.edu (John E. Davis) writes: > This is a BSD unix question. I to read a character in RAW mode from, say, >file descriptor 2. Raw turns off all input/output processing. However, I >only want input processing turned off. This is not the same as CBREAK. >CBREAK still does input processing on the special characters ^Z (stop), >^\ (quit), etc... which I want turned off. So my question is this: from >within a C program how do I accomplish the above objective? Well, it depends on what you do, and what you don't, want turned off. It also depends on what flavor of tty driver your OS has; you say "BSD UNIX", but also say >Note: I did RTFM but all it talked about was termio which our system >does not have (although for some stupid reason the man pages think so). > >A related question (perhaps the same question): It seems that from the shell, >I can type `stty -isig' to turn off input processing on the interrupt >characters (^Z, etc..). Given that you can type "stty -isig" from the shell, I'm skeptical of your claim that your system doesn't have "termio", because ISIG is a "termio"ism. The explanations I can think of are: 1) your system has "termios", but not "termio"; 2) your system has picked up some "termio"/"termios"isms, but not others. Precisely what OS are you running? If it's a BSD release prior to 4.3-reno, I'm curious how it got "isig". If it's 4.3-reno, it doesn't have "termio", but it *does* have "termios". >In BSD, how do I accomplish this with an ioctl? Well, if your system really truly genuinely doesn't have "termio" *or* "termios", the way you'd do it would be to go into CBREAK mode *and* "disable" the interrupt characters - and the XON/XOFF characters, if you want them "disabled" as well. To "disable" them, set them to '\377' using the TIOCGETC/TIOCSETC and TIOCGLTC/TIOCSLTC "ioctl"s; "disable" is in quotes because that doesn't really disable them, it merely sets them to a value unlikely to be seen (if you have 8-bit input turned on, they are, at best, unlikely, not impossible; if you have 8-bit input turned off, they are impossible). If your system *does* have "termio" or "termios", then turn ISIG off to disable all the interrupt characters (^C, ^Z, ^\), and turn IXON off to disable the XON/XOFF characters. You may also want to turn IEXTEN off, as that may be necessary to disable the literal-next (^V) and flush-output (^O) characters. In article <11914@dog.ee.lbl.gov> torek@elf.ee.lbl.gov (Chris Torek) writes: >In general, you want CS8 (8 data bits), optional parity, ISIG and ICANON >turned off, and OPOST turned on. Well, I'm not sure he said he wanted 8-bit input.... >If you have a BSD system without `stty -isig' and without TIOCGETA etc., >you can fake 8-bit input without disabling output processing by setting >LLITIN in the `local mode word', Setting *what*? "I see no LLITIN here." Do you mean "PASS8"?
torek@elf.ee.lbl.gov (Chris Torek) (04/11/91)
>In article <11914@dog.ee.lbl.gov> torek@elf.ee.lbl.gov (Chris Torek) writes: >>If you have [an old] BSD system ... you can fake 8-bit input without >>disabling output processing by setting LLITIN in the `local mode word', In article <7114@auspex.auspex.com> guy@auspex.auspex.com (Guy Harris) writes: >Setting *what*? "I see no LLITIN here." Do you mean "PASS8"? Oops, right. (PASS8 appeared in either 4.3 or 4.3-tahoe. `litout' mode had been around for quite some time before that, and I always thought of pass8 as `litin'.) -- In-Real-Life: Chris Torek, Lawrence Berkeley Lab CSE/EE (+1 415 486 5427) Berkeley, CA Domain: torek@ee.lbl.gov