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Comment by huhtenberg | Hacker News Reader

Using asserts AND keeping them in production builds.

This really helps whipping people into shape and making them pay attention to what they write. Also helps documenting the code in a very succinct way.

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And in terms of performance it costs next to nothing. Just don't put them into your critical loops.

You can also print backtraces when an assertion fails: https://stackoverflow.com/questions/77005/how-to-automatical...

Depends on what’s in your asserts. If, for example, you check validity of your custom data structure in an assert, even a single assert can cost a lot to more than nothing.

(Whether you should use assert for that kind of checks that probably only should run in tests is debatable, but it sometimes happens)

What really costs nothing is putting assert(0) in any place that should be unreachable. For example:

  switch (...) {
    case A:
      ...
    case B:
      ...
    ...
    default: // all possible cases are dealt with above
      assert(0);
  }

One ugly trick for unreachable branches is this:

    assert(!"You gave an invalid letter");

The string literal is a pointer, so !pointer is false. And then you get a nice explanation message when the assertion fails. I wish all assert gave optional explanation messages.

I often do assert(condition && "String explanation") myself.

For anyone following along. Don't do this if the code base is already hotshit. This will only make things worse and not prevent errors, just cause more outages.

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