I use that macro frequently but warily. The fact that it only works with static ... | Hacker News

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AceJohnny2 on Feb 13, 2015 | parent | context | favorite | on: C99 tricks

I use that macro frequently but warily. The fact that it only works with static arrays and (AFAIK) the compiler won't warn you if you accidentally use it on dynamic arrays/pointers/array parameters is a big risk.

Come to think of it, I'm afraid I'm leaving a time bomb for the next inexperienced maintainer who doesn't know the limitations.

RustyRussell on Feb 14, 2015 [–]

See the one I wrote for the Linux kernel; it will error at build time on a non-array (using tyoeof).

Even better, grab it from CCAN: http://ccodearchive.net/info/array_size.html

Cheers, Rusty.

AceJohnny2 on Feb 19, 2015 | [–]

Thanks!

I see you use __builtin_types_compatible_p, which looks very useful but also appears to be a GCC-specific.

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