container, error: update error handling

[eriksjolund]

What is the preferred way to write a check that indicates that a failure is not expected and that such a failure would indicate a programming errror?

One way is to write assert() (but such a check is only active for an executable that was compiled with the debug option enabled)

For example:

  assert(err != NULL);
  assert(*err != NULL);

This is another way:

if (err == NULL || *err == NULL) {
  // programming error
  _exit(EXIT_FAILURE);
}

I prefer assert() slightly more.