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Comment by rburhum | Hacker News Reader

Why would you overcomplicate your life and use something like the autofree example, that is not even portable, if you can use the heap which is simple to understand and do? I understand that if it is a hot function you may run into memory fragmentation/performance issues, but there are some many ways to deal with that with custom allocators if it truly is a problem. This is one of those perfect examples where simple is better IMHO

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The autofree example uses the heap. It just makes calling free() automatic when the function returns, regardless of where it does so. It's leak protection.

It's also wrong since __attribute__((cleanup)) expects a function that takes an additional level of pointer. In this case, it'll call "free(&scratchpad);". Which doesn't get you a compiler warning in C because passing a char ** as a void * is perfectly fine. But your heap is f*cked after this.

Correct way to do it is

  void free2(char **p)
  {
    free(*p);
  }
  #define autofree __attribute__((cleanup(free2)))

The proposed autofree example uses the heap with (unnecessary) preprocesor directives... but the problem is that it is not portable as written, vs simply using the heap like a normal person.

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