Nonblocking IO (ITI8510): erinevus redaktsioonide vahel
Mine navigeerimisribale
Mine otsikasti
| 14. rida: | 14. rida: | ||
'''Hints:''' | '''Hints:''' | ||
*Use open() with O_NONBLOCK flag, | *Use [http://linux.die.net/man/2/open open()] with O_NONBLOCK flag, | ||
* [http://en.wikipedia.org/wiki/Named_pipe FIFO] can be made with a 'mkfifo fifoname' command and written to using 'cat > fifoname'. | * [http://en.wikipedia.org/wiki/Named_pipe FIFO] can be made with a 'mkfifo fifoname' command and written to using 'cat > fifoname'. | ||
* You have to open fifo ''before'' reading (use two terminals). | * You have to open fifo ''before'' reading (use two terminals). | ||
* It helps to set output to non-buffered mode (the default is line-buffered). | * It helps to set output to non-buffered mode (the default is line-buffered). | ||
Redaktsioon: 18. veebruar 2010, kell 17:39
We have two tasks today. Both with practicing nonblocking IO.
1. Canonical mode
Goal: To write a program which echoes characters on screen while typed until button 'q' is pressed. Then prints a newline.
Hints:
- Try to put the terminal into noncanonical mode. See 'man termios' or [ Google for that.
- Note that you should restore the terminal mode before quitting since otherwise the terminal might get messed up (no echo).
2. Nonblocking reading from a FIFO
Goal: To write a program which prints a '.' character every half-a second unless some input is provided on a fifo file.
Hints: