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Re: help making a cmake check for _Atomic?

From: Cristian Rodríguez via curl-library <>
Date: Mon, 13 Jun 2022 09:04:25 -0400

On Mon, Jun 13, 2022 at 2:09 AM Daniel Stenberg <> wrote:
> On Sun, 12 Jun 2022, Cristian Rodríguez wrote:
> > so, if target environment is said to support c11 and not defined
> > __STDC_NO_ATOMICS__ then include header, define some internal flag else not
> > supported.
> That seems more complicated than what we do now.
> configure tests need to check for the presence of things, not the absense of
> the opposite.
> If you build curl with C89 compiler from the early 90s, __STDC_NO_ATOMICS__
> will not be defined even if atomic and friends are not supported.

Yes, but then __STDC_VERSION__ will not be defined to 201112L as
_Atomic depends on the memory model which was standarized by C11,
Received on 2022-06-13