OS X 10.6.3 broke ncurses

As I was working on my Seitunes project, I noticed something strange: the arrows didn’t quite work any more. Instead of their proper action (up & down to change volume, right & left to change song), they all quit the program and printed -respectively- “OA”, “OB”, “OC” and “OD” on the stdout.

I tried to go back to a working state by progressively deleting new features I was implementing, until I had exactly the same code as the (known working!) 0.5 version, but it was still quitting. gdb told me it wasn’t a crash (“Program exited normally”).

After some testing, I noticed Seitunes worked on my laptop, but not on my MacBook Pro. The only difference between them being that my laptop was still in OS X 10.6.2, while my mbp has upgraded to 10.6.3.

After a bit of digging into curses functions, I started to suspect keypad(WINDOW *, BOOL) to not work properly after the update. keypad() is supposed to dictate whether getch() should interpret an arrow as one non-ASCII value (with the boolean argument set to TRUE) or a set of ASCII values beginning by the escape char, a.k.a. 27 (FALSE). I explicitly call keypad(stdscr, TRUE) in Seitunes, but the FALSE state would perfectly explain the quit-then-print-two-chars behaviour I had was having: I use the escape character to quit Seitunes.

I wrote two very simple pieces of code -one for keypad true, one for keypad false- that plainly outputs the value returned by getch(). They look like:

#include <curses.h>

int main( int argc, char** argv )
	int key;
	intrflush(stdscr, FALSE);
	keypad(stdscr, TRUE);
	printw("getch() should produce only one value when hitting an arrow.\n");
	while ( (key = getch() ) != 'q' ) {
		printw("You entered key %d\n", key);	
	return 0;

Code and makefile available here (testCurses.zip) if you want to give it a try.

Under both OS X 10.6.2 and Linux Mint 6 “Felicia” (based on Ubuntu 8.10), these programs behave as they’re supposed to: when keypad is TRUE, an arrow is shown as a single value; when FALSE, an arrow becomes a set of values.

Under OS X 10.6.3, these two programs behave the same way. Both output several values for an arrow.

I filed a bug report to Apple (vintage interface by the way!).

While this bug is present, we’ll have to manually parse the ASCII values for the arrows, which are mapped as follows:

Up	27 79 65	('escape' 'O' 'A')
Down	27 79 66	('escape' 'O' 'B')
Right	27 79 67	('escape' 'O' 'C')
Left	27 79 68	('escape' 'O' 'D')

Edit: these values assume OS X 10.6.3 and keypad(stdscr, TRUE), a.k.a. when the bug is present.

If you want to use keypad(stdscr, FALSE) in 10.6.3, the arrows are mapped as:

Up	27 91 65	('escape' '[' 'A')
Down	27 91 66	('escape' '[' 'B')
Right	27 91 67	('escape' '[' 'C')
Left	27 91 68	('escape' '[' 'D')

Update, March 1st: Apple answered to my bugreport (ID #7812788). They told me it was a known issue (duplicate of bug #7812932) currently being investigated by engineering.

Insecure startup item disabled

As a follow-up to my post about startup items, I want to point out that a Startup Item must have proper permissions or it will be disabled at startup with the following message:

The error message saying a startup item has been disabled

In my case, the files under /Library/StartupItems/MyApache still belonged to me instead of root:wheel.

Fixed with a simple:

mbp:StartupItems florent$ sudo chown -Rv root:wheel /Library/StartupItems/MyApache/

It also appears that StartupItems permissions need to be set to 755 (executable/script file) and 644 (plist file) respectively.

Put OS X to sleep via command-line

When connecting to an OS X box via SSH, you may want to put it to sleep after you’re done.

This is no system call to put the computer to sleep that I know of. However, Applescript can do it, and it is trivial to call the OSAScript interpreter in bash.

The following script puts the computer to sleep:


osascript -e 'tell application "System Events" to sleep'

Edit: found a better way!

I don’t know if this is specific to Snow Leopard, but the following command will work as well without having to use Applescript or administrator rights:

pmset sleepnow

Seitunes, an iTunes command-line interface

My home main computer is a MacBook Pro, on which I frequently play music with iTunes. However, I’m often on my laptop, without direct access to the MBP’s screen or keyboard/mouse to pause, change song, change volume, etc. I can connect to the MBP using VNC, but I was looking for something more lightweight.

I therefore decided to design a command-line interface for iTunes, that I would run via SSH. I called it Seitunes for reasons I can’t really remember right now, but there it is!

Seitunes is

– written in C and interfaces with iTunes through AppleScript
– designed for OS X – should be compatible with quite old versions actually, because it doesn’t rely on a lot of cutting edge features
– built upon the curses library
– very very small
– still under development
– Free software (GPLv3)
– available here


> Display iTunes playing track and status

Seitunes main screen

> Control iTunes playback (play/pause, volume, next song/previous song)

Seitunes, main screen, playing, with help

> If iTunes is stopped when Seitunes starts, it starts iTunes and starts a song from the Library.

To do

> Add more tests to better check iTunes state and not trigger Applescript errors
> Add info about playlists in order to be able to play a specific playlist instead of the whole library
> Add an option to toggle shuffle
> Implement the “quit iTunes” function and check that it doesn’t cause more Applescript problems

Known bugs

> An error message flickers when an Applescript error is triggered (often when iTunes quit while Seitunes is opened)

On designing mockups

As part of a group project, I am currently involved in designing an application from the ground up. Designing the UI first drafts, before even chosing a programming language or environment, is something that should be easy and straightforward. We needed a tool that allows easy sharing between people, regardless of operating system.

Please welcome Mockingbird.

An amazing web application to design sleek and elegant UIs, Mockingbird is Javascript-based (no Flash!) and especially powerful if you’re working as part of a team or if you share a lot of mockups. Try it!