Linux does not have an equivalent to the conio.h getch() and kbhit() which respectively return a single character from the keyboard and return true if a key is waiting; to get this functionality it seems you have to play around with the termio structures... it expects to hand off a string when the return key is pressed, which is less than handy in some circumstances.
I'm using code based on this, but this displays my problem: the basic idea is
- if there's a key waiting
- grab it
- output it to the console
but the issue is that the output is delayed until the next key is pressed. Anyone know a way to stop this? It looks as if the putchar is being called when expected, but nothing on the console until the next key is ready - which is less than handy to type with. Any thoughts cheerfully accepted, thanks!
#include <stdio.h>
#include <stdlib.h>
#include <termios.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
void changemode(int);
int kbhit(void);
int main(void)
{
int ch;
while (1)
{
changemode(1);
while ( !kbhit() )
{
//putchar('.');
}
ch = getchar();
//printf("\nGot %c\n", ch);
putchar (ch);
changemode(0);
}
return 0;
}
void changemode(int dir)
{
static struct termios oldt, newt;
if ( dir == 1 )
{
tcgetattr( STDIN_FILENO, &oldt);
newt = oldt;
newt.c_lflag &= ~( ICANON | ECHO );
tcsetattr( STDIN_FILENO, TCSANOW, &newt);
}
else
{
tcsetattr( STDIN_FILENO, TCSANOW, &oldt);
}
}
int kbhit (void)
{
struct timeval tv;
fd_set rdfs;
tv.tv_sec = 0;
tv.tv_usec = 0;
FD_ZERO(&rdfs);
FD_SET (STDIN_FILENO, &rdfs);
select(STDIN_FILENO+1, &rdfs, NULL, NULL, &tv);
return FD_ISSET(STDIN_FILENO, &rdfs);
}Neil
