Include header for sycl::ext::oneapi::experimental::printf when SYCL support is detected

[masterleinad]

Detecting SYCL support in

mdspan/include/experimental/__p0009_bits/config.hpp

Lines 96 to 100 in 3c1aa52

	#ifndef MDSPAN_IMPL_HAS_SYCL
	# if defined(SYCL_LANGUAGE_VERSION)
	# define MDSPAN_IMPL_HAS_SYCL SYCL_LANGUAGE_VERSION
	# endif
	#endif

doesn't depend on the SYCL header sycl/sycl.hpp being included but we need this header for sycl::ext::oneapi::experimental::printf.

[masterleinad]

https://github.com/kokkos/mdspan/pull would have detected it (currently also includes this fix).

[tpadioleau]

https://github.com/kokkos/mdspan/pull would have detected it (currently also includes this fix).

Are you referring to #235 ?

[masterleinad]

Are you referring to #235 ?

Yes, that one also includes the fix now. I'll leave it up to those with merge authority if we want to merge the fix and improving the CI separately.

[crtrott]

Why is it not enough that this include is included in the one file which defines a macro using the SYCL printf?

[masterleinad]

Why is it not enough that this include is included in the one file which defines a macro using the SYCL printf?

That is this file.

[jcrthack]

I think sycl::ext::oneapi::experimental::printf has been removed from the more recent intel compiler versions. I have to remove it from the macros or else get a compilation error with the compiler:

Intel(R) oneAPI DPC++/C++ Compiler 2025.3.0 (2025.3.0.20251010)

I am wondering if it is possible to just remove sycl::ext::oneapi::experimental::printf entirely?

I do this and it fixes my problem.

Example:

#include <experimental/mdspan>
#include <iostream>
#include <vector>

auto main() -> int {

  auto vec = std::vector<double>{1, 2, 3, 4};

  auto mat = std::mdspan{vec.data(), 2, 2};

  for (auto i = 0UZ; i < mat.extent(0); ++i) {
    for (auto j = 0UZ; j < mat.extent(1); ++j) {
      std::cout << mat[i, j] << "\n";
    }
  }
}

>>> icpx -fsycl test.cc -o test -I ./mdspan/include/ -std=c++23
In file included from test.cc:1:
In file included from ./mdspan/include/experimental/mdspan:27:
In file included from ./mdspan/include/experimental/../mdspan/mdspan.hpp:28:
In file included from ./mdspan/include/experimental/../mdspan/../experimental/__p0009_bits/default_accessor.hpp:18:
./mdspan/include/experimental/../mdspan/../experimental/__p0009_bits/macros.hpp:122:9: error: no member named 'ext' in namespace 'sycl'
  122 |   sycl::ext::oneapi::experimental::printf("%s:%u: precondition failure: `%s`\n", file, line, cond);
      |   ~~~~~~^
1 error generated.

it compiles and runs fine if the -fsycl flag is removed.

[tpadioleau]

It seems the definition is still present in /opt/intel/oneapi/2025.3/include/sycl/ext/oneapi/experimental/builtins.hpp, maybe a problem of header inclusion ?

[jcrthack]

It seems the definition is still present in /opt/intel/oneapi/2025.3/include/sycl/ext/oneapi/experimental/builtins.hpp, maybe a problem of header inclusion ?

You are correct, I made a mistake when searching for the printf function in the dir.

including the builtins header within the macros.hpp fixes the problem.

[jcrthack]

Apologies, I have made another mistake. This branch fixes the problem. My comments can all be ignored. Sorry for the confusion!