Irve – 27. september 2019, kell 08:59

2019-09-27T08:59:52Z

Irve: Uus lehekülg: '{{Its8020}} Practice with nonblocking IO. = 1. Canonical mode = Goal: To write a program which echoes characters on screen while typed until button 'q' is pressed. Then it qui...'

2019-09-27T08:47:09Z

Uus lehekülg: '{{Its8020}} Practice with nonblocking IO. = 1. Canonical mode = Goal: To write a program which echoes characters on screen while typed until button 'q' is pressed. Then it qui...'

Uus lehekülg

{{Its8020}}

Practice with nonblocking IO.

= 1. Canonical mode =

Goal: To write a program which echoes characters on screen while typed until button 'q' is pressed. Then it quits and prints a newline.

'''Hints:'''
* Try to put the terminal into noncanonical mode and remove terminal echo See '[http://linux.die.net/man/3/termios man termios]' or [http://www.google.ee/search?q=noncanonical+mode Google "noncanonical mode"] for that.
* Note that you should restore the terminal mode before quitting since otherwise the terminal might get messed up (no echo).
* Working with bits:
flags &= ~NEWFLAG // Clears the bit NEWFLAG on flags
flags |= NEWFLAG // Set the bit NEWFLAG on flags
flags ^= NEWFLAG // Toggle NEWLAG

= 2. Nonblocking reads 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:'''
* Use [http://linux.die.net/man/2/open open()] with O_NONBLOCK flag.
* If [http://linux.die.net/man/2/read read()] does not have anything to read, it returns with -1 and sets [http://linux.die.net/man/3/errno errno] to constant EAGAIN - you can check that or try messing around with [http://linux.die.net/man/3/select select()] function.
* [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 (open two terminal windows).
* Write your output with [http://linux.die.net/man/2/write write()] function to bypass line buffering (or turn it off).
* Function usleep() can be used for half-a second pause here.

[[Kategooria:RTOS]]

@@ 3. rida: / 3. rida: @@
 Practice with nonblocking IO.
-Goal: To write a program which echoes characters on screen while typed until button 'q' is pressed. Then it quits and prints a newline.
+= 1. Nonblocking reads from a FIFO =
 '''Hints:'''
-* Try to put the terminal into noncanonical mode and remove terminal echo See '[http://linux.die.net/man/3/termios man termios]' or [http://www.google.ee/search?q=noncanonical+mode Google "noncanonical mode"] for that.
+* Try to put the terminal into noncanonical mode (you want to turn off line buffering) and remove terminal echo See '[http://linux.die.net/man/3/termios man termios]' or [http://www.google.ee/search?q=noncanonical+mode Google "noncanonical mode"] for that.
 * Note that you should restore the terminal mode before quitting since otherwise the terminal might get messed up (no echo).
 * Working with bits:
@@ 15. rida: / 17. rida: @@
   flags ^= NEWFLAG    // Toggle NEWLAG
-Goal: To write a program which prints a '.' character every half-a second unless some input is provided on a fifo file.
+= 2. Reading from stidin =
 '''Hints:'''

Nonblocking IO (ITS8020) - Redigeerimiste ajalugu

Irve – 27. september 2019, kell 08:59

Irve: Uus lehekülg: '{{Its8020}} Practice with nonblocking IO. = 1. Canonical mode = Goal: To write a program which echoes characters on screen while typed until button 'q' is pressed. Then it qui...'