Can I avoid read to wait for input

Asked Nov 06 '19 at 13:15

Active Nov 06 '19 at 13:55

Viewed 99 times

I'm trying to make a C version of Snake. This is the situation: set_input_mode() is used to change the terminal behaviour to not echo character and take it one at time, when i press a key i want the snake to turn in that direction and continue, but he keeps waiting for the read() to give him something. How can I avoid this behaviour? (The full code is avaiable here)

int main(){
char c;
set_input_mode();
while(1){
  read(0, &c, 1);

switch(mv)
all the cases..
}
}


void set_input_mode (){
struct termios tattr;
char *name;

/* Make sure stdin is a terminal. */
if (!isatty (STDIN_FILENO))
  {
    fprintf (stderr, "Not a terminal.\n");
    exit (EXIT_FAILURE);
  }

/* Save the terminal attributes so we can restore them later. */
tcgetattr (STDIN_FILENO, &saved_attributes);
atexit (reset_input_mode);

/* Set the terminal modes. */
tcgetattr (STDIN_FILENO, &tattr);
tattr.c_lflag &= ~(ICANON|ECHO); /* Clear ICANON and ECHO. */
tattr.c_cc[VMIN] = 1;
tattr.c_cc[VTIME] = 0;
tcsetattr (STDIN_FILENO, TCSAFLUSH, &tattr);
}

edited Nov 06 '19 at 13:55

asked Nov 06 '19 at 13:15

Seth

3

Links to code are not optimal here. Post the code you have a question about. It should be a [mcve], with clearly stated problem. – ryyker Nov 06 '19 at 13:18
1

Multiple threads, asynchronous IO, non-blocking IO.... – Ed Heal Nov 06 '19 at 13:18
This example does not compile, the problem is not reproducible. – David Wright Nov 06 '19 at 13:46
2

Possible duplicate of [Non-blocking call for reading descriptor](https://stackoverflow.com/questions/5616092/non-blocking-call-for-reading-descriptor) Just set `O_NONBLOCK`. – KamilCuk Nov 06 '19 at 13:55
@KamilCuk where i have to add O_NONBLOCK? – Seth Nov 06 '19 at 13:59
1

Follow the link. The example usage of `fcntl` is right there. – KamilCuk Nov 06 '19 at 14:00
@KamilCuk it worked, thanks – Seth Nov 06 '19 at 14:08

Can I avoid read to wait for input

0 Answers0