dpct/dpct.hpp (device.hpp) requires c++17 feature

[yhmtsai]

Hi,

Is C++17 in the dpct requirement?

If I compile the following codes with -std=c++14 or -std=c++17 on devcloud, compilation will fail.

#include <CL/sycl.hpp>
#include <dpct/dpct.hpp>
#include <iostream>

int main() {
    std::cout << "Hello Devcloud" << std::endl;
    return 0;
}

The compile command:

dpcpp hello.dp.cpp -std=c++11
dpcpp hello.dp.cpp -std=c++14
dpcpp hello.dp.cpp -std=c++17

dpct/device.hpp uses std::max_element which is introduced in C++17.

The error message:

In file included from hello.dp.cpp:2:
In file included from /glob/development-tools/versions/oneapi/beta09/inteloneapi/dpcpp-ct/2021.1-beta09/include/dpct/dpct.hpp:27:
/glob/development-tools/versions/oneapi/beta09/inteloneapi/dpcpp-ct/2021.1-beta09/include/dpct/device.hpp:218:16: error: no member named 'max_element' in namespace 'std'
          std::max_element(sub_group_sizes.begin(), sub_group_sizes.end());
          ~~~~~^
1 error generated.

Thanks,
Mike

[GouthamK_Intel · Accepted solution]

Hi Mike,

Yes, dpct headers require C++17, as some of the std algorithms in those dpct header files are based on C++17 standard.

And regarding "If I compile the following codes with -std=c++14 or -std=c++17 on devcloud, compilation will fail."

we assume that you meant -std=c++11 and -std=c++14 gives compilation error.

We have compiled your code on devcloud with c++11, c++14, c++17 and we observed that c++11 and c++14 gives errors. Whereas, code compiles, and executes successfully with -std=c++17.

Also, by default devcloud uses c++17 standard, so there is no need to use --std flag.

If you are facing this issue with -std=c++17 itself then please provide the error logs.

Have a Good day!

Regards

Goutham

[yhmtsai]

Hi Goutham,

"If I compile the following codes with -std=c++14 or -std=c++17 on devcloud, compilation will fail."
Yes, I wrote wrong statement here, sorry. it is failed with -std=c++11 and -std=c++14.

I see.
The reason behind this problem is that our project currently is on -std=c++14.
We would like to keep same requirement among different module.
If the requirement is c++17, we probably need to compile whole project with c++17 when enabling intel.
or, compile intel with c++17 and others with c++14. I am not sure whether it work or not.

Thanks,
Mike

[GouthamK_Intel]

Hi Mike,

As dpct requires std=C++17, you can try either one of the mentioned methods by you as per your project requirement/ flexibility.

If you face any further challenges or errors, please feel free to raise a new thread.

Could please confirm If we have answered all your queries in the current thread and lets us know if we can close this thread from our side.

Have a Good day!

Thanks & Regards

Goutham

[yhmtsai]

Hi Goutham,

Yes, you have answered my questions in this current thread.
Thanks a lot!

Regards,
Mike

[GouthamK_Intel]

Hi Mike,

Thanks for the confirmation!

As this issue has been resolved, we will no longer respond to this thread. 

If you require any additional assistance from Intel, please start a new thread. 

Any further interaction in this thread will be considered community only. 

Have a Good day!

Thanks & Regards

Goutham