Breathturn by Hammock

What a stunningly beautiful music video…

Hammock – Breathturn from David Altobelli on Vimeo.

GCC Undefined Behavior

Check out this little GCC gem that I just discovered read about.

In GCC 1.17, when the compiler encountered specific forms of undefined behavior (unknown/not implemented #pragmas), here’s the code it executed:

execl("/usr/games/hack", "#pragma", 0); // try to run the game NetHack

execl("/usr/games/rogue", "#pragma", 0); // try to run the game Rogue

// try to run the Tower's of Hanoi simulation in Emacs.
execl("/usr/new/emacs",  "-f","hanoi","9","-kill",0);

execl("/usr/local/emacs“,"-f“,"hanoi“,"9“,"-kill“,0); // same as above

fatal("You are in a maze of twisty compiler features, all different");

When GCC identified “bad” C++ code, it tried to start NetHack, Rogue, or Towers of Hanoi. Failing all three, GCC printed out a cryptic error message. Wow.

This just goes to show you that when the official C++ specification talks about undefined behavior, they mean business:

[Undefined behavior is] behavior, such as might arise upon use of an erroneous program construct or erroneous data, for which the Standard imposes no requirements

No requirements indeed.

Update: It turns out this is actually implementation-defined behavior, which is slightly different than undefined behavior. Implementation-defined behavior actually requires the compiler to document what it does, but there are no requirements on what it can do.

Copying Is Not Theft

When artists do work, they should be paid — no one is debating that. Musicians are paid when they perform at concerts, when they sell discs, and when they compose for someone. Artists are paid when they sell their artwork, when they are commissioned to make art, and when their art appears in art museums.

However, artists shouldn’t chase down and sue every adolescent who copies their work without advance permission. The job of artists is to create stuff — and for that they should be compensated. They should not necessarily be compensated for the distribution of their work, especially when computers and the Internet make it trivial to distribute bits at a near-zero cost.

At the end of the day, artists should be paid when they make stuff. Mozilla is a great example of a company that understands this. Let’s say that software engineers are artists for the sake of this example (in many ways, we are artists). So, Mozilla engineers get paid when they’re designing, programming, and submitting patches for Firefox, Thunderbird, and SeaMonkey. Yet, when the time comes for the software to be distributed, Mozilla engineers are not paid anything. All Mozilla software is free (as in freedom) and open source, as governed by the Mozilla Public License. Read the rest of this entry »

Misinterpreting Copyright

I just read a great article about copyright that articulates the free software position extremely well. It’s written by Richard Stallman, the guy who started the free software movement.

Some highlights:

The copyright bargain places the public first: benefit for the reading public is an end in itself; benefits (if any) for publishers are just a means toward that end. Readers’ interests and publishers’ interests are thus qualitatively unequal in priority.

This is why our discussion about copyright is so unbalanced today. People need to remember that the public is more important than the publisher. Read the rest of this entry »