Paul Eggert wrote:
> On 10/10/20 8:04 AM, Marc Nieper-Wißkirchen wrote:
> > #if defined (__STDC_VERSION__) && __STDC_VERSION__ >= 201112L &&
> > !defined (__STD_NO_ATOMICS__)
> >
> > I am asking because there may be non-C11 compilers that nevertheless
> > understand _Atomic.
>
> I suggest not worrying about this problem until we run into it.
GCC 4.9.x is such a compiler that is non-C11 but supports _Atomic.
With this test program
==================================================================
#include <stdio.h>
#if defined (__STDC_VERSION__) && __STDC_VERSION__ >= 201112L \
&& !defined (__STD_NO_ATOMICS__)
# define GL_HAMT_THREAD_SAFE 1
#else
# define GL_HAMT_THREAD_SAFE 0
#endif
_Atomic int x;
void increment_x (void)
{
x++;
}
int main (void)
{
printf ("GL_HAMT_THREAD_SAFE=%d\n", GL_HAMT_THREAD_SAFE);
return 0;
}
==================================================================
the results on the various platforms are as follows:
GL_HAMT_THREAD_SAFE _Atomic compiles _Atomic works
GCC 4.8 0 0 0
GCC 4.9 0 1 1
GCC 5 1 1 1
GCC 6 1 1 1
GCC 7 1 1 1
GCC 8 1 1 1
GCC 9 1 1 1
GCC 10 1 1 1
macOS 10.13 1 1 1
FreeBSD 12 1 1 1
NetBSD 9 1 1 1
OpenBSD 6.7 cc 1 1 1
OpenBSD 6.7 gcc 0 0 0
AIX 7.1 xlc 0 0 0
Solaris 10 cc 0 0 0
Solaris 11.3 cc 12.4 0 0 0
Solaris 11.3 cc 12.5 1 1 1
Solaris 11.3 cc 12.6 1 1 1
MSVC 14 0 0 0
Bruno
