<stdatomic.h> in GCC 4.8?

c multithreading gcc atomic c11
Patrick Collins picture Patrick Collins · Dec 2, 2013 · Viewed 21k times · Source

I'd like to make use of the new atomic operations provided by the C11 standard. However, trying to #include the appropriate header file gives me this:

 csort-par.c:5:23: fatal error: stdatomic.h: No such file or directory
 #include <stdatomic.h>

The documentation at http://gcc.gnu.org/wiki/C11Status seems to say that the header file has been provided since GCC 4.7... am I missing something? __STDC_NO_ATOMICS__ is not defined.

gcc --version is as follows:

gcc (Ubuntu/Linaro 4.8.1-10ubuntu9) 4.8.1
Copyright (C) 2013 Free Software Foundation, Inc.

And I confirmed that __STDC_NO_ATOMICS__ was not defined as follows:

#ifdef __STDC_NO_ATOMICS__
#error yes
#else
#error no
#endif

yields:

csort-par.c:10:2: error: #error no
 #error no

EDIT: Thanks for the swift replies.

In case anyone stumbles on this from Google with the same question, here's a fix in the interim until they release GCC 4.9:

UNIX Portable Atomic Operations

Answer

keltar picture keltar · Dec 2, 2013

This file is missing. http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58016

It was fixed only in gcc 4.9, as its release notes says (http://gcc.gnu.org/gcc-4.9/changes.html)

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