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TeX 1995 July
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TeX CD-ROM July 1995 (Disc 1)(Walnut Creek)(1995).ISO
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dvitovdu32
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src
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pascal
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unixio.c
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C/C++ Source or Header
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1991-11-10
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124 lines
/* Alex Dickinson
Procedures for setting and resetting UNIX tty characteristics.
Interesting functions are:
savetty;
restoretty;
echoon;
echooff;
singlecharon;
singlecharoff;
buffercount;
suspend;
A side effect of calling savetty is to set up signal handling to reset
the terminal characteristics appropriately for the various interrupt
signals.
*/
#include <stdio.h>
#include <sgtty.h>
#include <signal.h>
struct sgttyb initchars; /* store initial terminal characteristics */
/* Save the original tty characteristics and set up the signalling. */
savetty()
{
ioctl(1, TIOCGETP, &initchars);
setsignals();
}
/* Restore the original tty characteristics. */
restoretty()
{
ioctl(1, TIOCSETN, &initchars);
}
/* Set driver to read characters as they are typed without waiting for a
terminator. Echo remains unchanged. */
singlecharon()
{
struct sgttyb s;
ioctl(1, TIOCGETP, &s);
s.sg_flags |= CBREAK;
ioctl(1, TIOCSETN, &s);
fflush(stdin);
}
/* Turn off single character read mode. */
singlecharoff()
{
struct sgttyb s;
ioctl(1, TIOCGETP, &s);
s.sg_flags &= ~CBREAK;
ioctl(1, TIOCSETN, &s);
}
/* Turn character echoing on. */
echoon()
{
struct sgttyb s;
ioctl(1, TIOCGETP, &s);
s.sg_flags |= ECHO;
ioctl(1, TIOCSETN, &s);
}
/* Turn character echoing off. */
echooff()
{
struct sgttyb s;
ioctl(1, TIOCGETP, &s);
s.sg_flags &= ~ECHO;
ioctl(1, TIOCSETN, &s);
}
/* Return the number of characters currently in the input buffer. */
int buffercount()
{
long count;
ioctl(1, FIONREAD, &count);
return(count);
}
/* Yukko */
realungetc(ch, filed)
char ch;
int filed;
{
ioctl(filed, TIOCSTI, &ch);
}
/* Catch signals from tty.
If sig is an interrupt, put 0 and terminator into the buffer.
Otherwise it was a suspend, so we put 1 and terminator into buffer. */
handleint(sig)
int sig;
{
fflush(stdin);
if (sig == SIGINT)
{
realungetc(0, 0);
realungetc(13, 0);
}
else
{
realungetc(1, 0);
realungetc(13, 0);
}
}
/* Signal initialization. */
setsignals()
{
signal(SIGINT, handleint);
signal(SIGTSTP, handleint);
}
/* Suspend the process */
suspend()
{
signal(SIGTSTP, SIG_DFL);
kill(0, SIGTSTP);
/* resumed again, goody! */
setsignals();
}