I'm trying to compile some code with the CUDA SDK 5.5 RC and g++ 4.7 on MacOS X 10.8. If I understand correctly CUDA 5.5 should work with g++ 4.7. Looking at /usr/local/cuda/include/host_config.h it should even work with g++ 4.8.
Concerning g++ 4.8: I tried to compile the following program:
// example.cu
#include <stdio.h>
int main(int argc, char** argv) {
printf("Hello World!\n");
return 0;
}
But it fails:
$ nvcc example.cu -ccbin=g++-4.8
/usr/local/Cellar/gcc48/4.8.1/gcc/include/c++/4.8.1/cstdlib(178): error: identifier "__int128" is undefined
/usr/local/Cellar/gcc48/4.8.1/gcc/include/c++/4.8.1/cstdlib(179): error: identifier "__int128" is undefined
2 errors detected in the compilation of "/tmp/tmpxft_00007af2_00000000-6_example.cpp1.ii".
The same program compiles and runs with g++ 4.7:
$ nvcc example.cu -ccbin=g++-4.7
$ ./a.out
Hello World!
But if I include <limits>...
// example_limits.cu
#include <stdio.h>
#include <limits>
int main(int argc, char** argv) {
printf("Hello World!\n");
return 0;
}
... even g++ 4.7 fails. The build log is located here: https://gist.github.com/lysannschlegel/6121347
There you can find also a few other errors, I'm not totally sure if they are all related to __int128 missing.
It could well be that other standard library includes break the build on g++ 4.7 as well, limits is the one I tripped over.
I also tried g++ 4.5 because I happen to have it on my machine as well (you can never have too many compiler versions, can you?), and it works.
Can I expect that this will be fixed in the release of CUDA 5.5? (I hope NVIDIA doesn't simply go back to supporting gcc only up to version 4.6.)
Is there a way to work around this in the meantime?
UPDATE:
As @talonmies points out below, this is not strictly a bug in CUDA 5.5 on MacOS as gcc is not officially supported on MacOS. As many third-party libraries don't properly handle the supported toolchains, clang or llvm-gcc (llvm-gcc being from 2007....), there is still a need to make the gcc work. gcc up to 4.6 should work fine (I tested 4.5 only).
You can make gcc 4.7 work using the trick pointed out by @BenC in the comments:
$ cat compatibility.h
#undef _GLIBCXX_ATOMIC_BUILTINS
#undef _GLIBCXX_USE_INT128
$ nvcc example_limits.cu -ccbin=g++-4.7 --pre-include compatibility.h
nvcc with gcc 4.8 still chokes on __int128 in cstdlib. I guess cstdlib is included before --pre-include files are included.
You need to read the MacOS getting started guide more closely:
To use CUDA on your system, you will need the following installed:
CUDA-capable GPU
‣ Mac OSX v. 10.7.5 or later
‣ The gcc or Clang compiler and toolchain installed using Xcode
‣ NVIDIA CUDA Toolkit (available at http://developer.nvidia.com/cuda-downloads)
That means precisely what it says - use the compiler(s) that ships with Xcode. Don't use a self-built gcc version because it isn't guaranteed to work, even if that compiler version is listed as being supported on other platforms and if trivial code appears to compile correctly.