[libc-commits] [PATCH] D71094: [libc] Add implementation of errno.

[Fangrui Song via Phabricator via libc-commits]

MaskRay requested changes to this revision.
MaskRay added inline comments.
This revision now requires changes to proceed.


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Comment at: libc/config/linux/api.td:33
+  let Defn = [{
+    extern int *__errno_location();
+    #define errno *__errno_location()
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abrachet wrote:
> We don't use `extern` for other function definitions in other header files so I don't think we should here
You need `__attribute__((const))` in `__GNUC__` mode, otherwise common subexpression elimination does not apply: think `errno+errno`.


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https://reviews.llvm.org/D71094