Skip to main content

Autotools

Seriously, I write this blog for two simple reasons: the freebies and the groupies. Without them it wouldn't be worth it. And what great freebies: a DisplayLink USB video adapter and more RelaxZen than you can shake a stick at.

And the groupies. Well I have the photos, but I'm not posting them.

Which brings me to this week's awesome freebie: a copy of John Calcote's Autotools: A Practitioner's Guide To GNU Autoconf, Automake, AND Libtool. Yeah, that's what you get for living the GNU Make life and writing a self-published book about it.


If there was ever a tool that needed a book it's Autoconf (and related scripts). Happily, Calcote has done a great job of describing, in detail, a collection of tools that can seem opaque at first glance (also at second glance). This book is vital for anyone who needs to work with Autotools and I wish I'd had it years ago.

The final chapter (A catalog of tips and reusable solutions for creating great projects) is fantastic because it dishes up a collection of practical, real solutions to problems users of Autotools will encounter. Above all, the book shows that it was written by someone who truly understands the set of tools, and thankfully is able to write clearly.

He doesn't shy away from getting into difficult details (like the M4 macro language) and chapters 8 and 9 are an exposition of the use of Autotools for an actual, large project showing what a real-world use of the tools looks like. Those 50 pages are probably the most valuable in the entire book.

Highly recommended for anyone who needs to use Autotools.

Comments

Thanks for the review. I think I'll buy it! I also found this an excellent turorial

Popular posts from this blog

Your last name contains invalid characters

My last name is "Graham-Cumming". But here's a typical form response when I enter it:


Does the web site have any idea how rude it is to claim that my last name contains invalid characters? Clearly not. What they actually meant is: our web site will not accept that hyphen in your last name. But do they say that? No, of course not. They decide to shove in my face the claim that there's something wrong with my name.

There's nothing wrong with my name, just as there's nothing wrong with someone whose first name is Jean-Marie, or someone whose last name is O'Reilly.

What is wrong is that way this is being handled. If the system can't cope with non-letters and spaces it needs to say that. How about the following error message:

Our system is unable to process last names that contain non-letters, please replace them with spaces.

Don't blame me for having a last name that your system doesn't like, whose fault is that? Saying "Your last name …

All the symmetrical watch faces (and code to generate them)

If you ever look at pictures of clocks and watches in advertising they are set to roughly 10:10 which is meant to be the most attractive (smiling!) position for the hands. They are actually set to 10:09.14 if the hands are truly symmetrical. CC BY 2.0image by Shinji
I wanted to know what all the possible symmetrical watch faces are and so I wrote some code using Processing. Here's the output (there's one watch face missing, 00:00 or 12:00, because it's very boring):



The key to writing this is to figure out the relationship between the hour and minute hands when the watch face is symmetrical. In an hour the minute hand moves through 360° and the hour hand moves through 30° (12 hours are shown on the watch face and 360/12 = 30).
The core loop inside the program is this:   for (int h = 0; h <= 12; h++) {
    float m = (360-30*float(h))*2/13;
    int s = round(60*(m-floor(m)));
    int col = h%6;
    int row = floor(h/6);
    draw_clock((r+f)*(2*col+1), (r+f)*(row*2+1), r, h, floor(m…

The Elevator Button Problem

User interface design is hard. It's hard because people perceive apparently simple things very differently. For example, take a look at this interface to an elevator:


From flickr

Now imagine the following situation. You are on the third floor of this building and you wish to go to the tenth. The elevator is on the fifth floor and there's an indicator that tells you where it is. Which button do you press?

Most people probably say: "press up" since they want to go up. Not long ago I watched someone do the opposite and questioned them about their behavior. They said: "well the elevator is on the fifth floor and I am on the third, so I want it to come down to me".

Much can be learnt about the design of user interfaces by considering this, apparently, simple interface. If you think about the elevator button problem you'll find that something so simple has hidden depths. How do people learn about elevator calling? What's the right amount of informati…