Category: Computer Science

  • A Guide to Undefined Behavior in C and C++, Part 3

    Also see Part 1 and Part 2. A C or C++ implementation must perform side effecting operations in program order. For example, if a program executes these lines of code: printf (“Hello\n”) printf (“world.\n”); It is impermissible for the implementation to print: world. Hello This is obvious, but keep in mind that other things your […]

  • Running an Electronic Program Committee Meeting

    Computer science — at least in the areas that I work in — is conference-driven. Since journals go unread, it’s important that conference program committees make good decisions about which papers to accept. The established way to do this is to hold a program committee (PC) meeting: the entire committee holes up in a highly […]

  • Is Attending Meetings a Signaling Behavior?

    Humans and other animals spend a lot of time engaging in signaling behaviors: dressing or acting in certain ways in order to send signals to others. Some signals — a peacock’s tail or a Ferrari — are expensive precisely to show that the signaling organism can afford the cost of sending the signal. Signaling can […]

  • A Guide to Undefined Behavior in C and C++, Part 2

    Also see Part 1 and Part 3. When tools like the bounds checking GCC, Purify, Valgrind, etc. first showed up, it was interesting to run a random UNIX utility under them. The output of the checker showed that these utility programs, despite working perfectly well, executed a ton of memory safety errors such as use […]

  • Why Would Researchers Oppose Open Access?

    Last week I started sort of a relaxed flame war with other members of the steering committee for an ACM conference on the subject of open access to the proceedings. “Open access” would mean that anyone could download the proceedings. The current situation is slightly different: Often, individual papers are available on authors’ home pages. […]

  • A Guide to Undefined Behavior in C and C++, Part 1

    Also see Part 2 and Part 3. Programming languages typically make a distinction between normal program actions and erroneous actions. For Turing-complete languages we cannot reliably decide offline whether a program has the potential to execute an error; we have to just run it and see. In a safe programming language, errors are trapped as […]

  • How to Debug

    One of the painful parts of teaching a lab-based embedded systems course is that over and over I have to watch a team with a relatively simple bug in their code, but who is trying to fix it by repeatedly making random changes. Generally they start with code that’s pretty close to working and break […]

  • I Can Solve the World’s Debugging Problems

    Probably 10 times a semester, a student taking one of my courses sends me a mail like this: Dr. Regehr I have this bug I’ve been working on for a long time, I’ve tried everything, I’m going to miss the deadline… and then 15 minutes later, I get another email: Nevermind I figured it out. […]

  • The Truth About the Life of the Mind

    [This piece is a followup to The Big Lie About the Life of the Mind.] Being a professor, like any other job, has its pros and cons. You’d hope that one of the advantages would be that the job encourages a person to live a life of the mind. Otherwise what’s the point, right?  I […]

  • The Big Lie About the Life of the Mind

    Earlier this year Thomas Benton wrote an essay The Big Lie About the ‘Life of the Mind, skewering academic humanities in the United States. His thesis is that there is effectively a conspiracy to produce many more PhDs than there are faculty slots, and to keep the carrot of the tenure-track faculty position just out […]