Error in stdatomic_helper.h while compiling with gcc version > 5

[firesurfer]

I get the following error while compiling ROS2 with gcc (Debian 5.3.1-4) 5.3.1 20151219

error: missing binary operator before token "("
 #elif defined(__clang__) && defined(__has_feature) && !__has_feature(c_atomic)

It compiles when I change line 23 in stdatomic_helper.h from

#elif defined(__clang__) && defined(__has_feature) && !__has_feature(c_atomic)

to

#elif defined(__clang__) && defined(__has_feature) 

on my server with gcc (Debian 4.9.2-10) 4.9.2 it compiles without any errors.

[wjwwood]

Interesting, thanks. I guess the evaluation of the conditional doesn't stop when defined(__has_feature) is false.

I suppose we can try something like this:

#elif defined(__clang__) && defined(__has_feature)
#if !__has_feature(c_atomic)
...
#endif
...

[wjwwood]

@firesurfer if you have a chance, can you try the above and let me know if it works? I don't have a GCC 5 machine handy. If not I can set one up later.

[firesurfer]

Hey,
if I change it to:

#elif defined(__clang__) && defined(__has_feature) 
#if !__has_feature(c_atomic)
// If Clang and no c_atomics (true for some older versions), use the compatability header.
#include "stdatomic_helper/gcc/stdatomic.h"
#endif

it compiles.

[wjwwood]

I proposed this as a fix: #14