Stupid Smart Pointers in C

rwmj · 2025-03-17T12:14:54 1742213694

Really, don't do this, it's a portability and safety nightmare (aside from C not being memory safe already).

C programmers are better off with either of these two techniques:

* Use __attribute__((cleanup)). It's available in GCC and Clang, and we hope will be added to the C spec one day. This is widely used by open source software, eg. in systemd.

* Use a pool allocator like Samba's talloc (https://talloc.samba.org/talloc/doc/html/libtalloc__tutorial...) or Apache's APR.

(I didn't include using reference counting, since although that is also widely used, I've seen it cause so many bugs, plus it interacts badly with how modern CPUs work.)

pjdesno · 2025-03-17T12:10:17 1742213417

Note that this will probably cause branch prediction misses, just like thread switching does - modern CPUs have a return address predictor which is just a simple stack. I don’t think you can avoid this without compiler support.

adrianN · 2025-03-17T12:04:28 1742213068

I wonder how that affects compiler optimization

dhsysusbsjsi · 2025-03-17T12:14:36 1742213676

and stack protection cookies

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