C compiler lies about c11 support

The C compiler accepts the option '-std=c11' and responds by defining the define token '__STDC_VERSION__' = 201112 which thereby claims C11 support. Additionally, it DOES NOT define '__STDC_NO_THREADS__' and therefore the include headers <threads.h> and <stdatomic.h> should exist but they dont. The compiler is promising C11 threads, condition variables, ... support but does NOT provide it. This is NOT a link time problem, it is a compile time issue.

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skode
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I didnt specifiy but I need a work around because I promised to write some code that it turns out I cant easily deliver without a lot of extra work. I need a solution ASAP but unfortunately I expect that I am just plain screwed for the next year or two.

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skode
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I think you're stuck, sorry. Please do file a bug about our non-compliance. (FWIW, <stdatomic.h> is present in Xcode 7, but <threads.h> still isn't.)

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SevenTenEleven
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I was having problems with -std=c11 too so I switched to -std-gnu11 and it worked for _Generic and stdatomic.h. Strangely I switched back to -std=c11 and it worked. However threads.h , and unicode support are not available as of this date. If you really need unicode support you have the option of gcc.

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Dfrancis530
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if you're compiling for OSX why don you use gcc?

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iPad_dev
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Is there any updates? I still can't find <threads.h> and no STDC_NO_THREADS definition when creating command-line tool using C.

Posted by
HangRen
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  • Update: Sorry for not checking thoroughly, the macro STDC_NO_THREADS is defined when I create a new empty C project. But I still wonder if there is any plan for shipping supports for C11 threads?

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    HangRen
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But I still wonder if there is any plan for shipping supports for C11 threads?

We can’t talk about The Future™ here on DevForums. We already have a bug on file requesting C11 threads support (r. 71334589), but if this is important to your I recommend that you file your own bug requesting it, with an explanation as to why.

I believe there are various open source libraries that implement C11 threads on top of pthreads, so you could use one of those in the meantime.

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eskimo
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