Error when trying to compile a program with '.c' extension

[mingodad]

When trying to compile the sample program shown bellow with the '.c' extension it gives this error:

circle -o hello hello.c
error: target declarations:1:1
undeclared identifier 'class'
enum class nvvm_arch_t { 
^

error: target declarations:3:1
undeclared identifier 'class'
enum class amdgpu_arch_t { 
^

error: target declarations:17:23
undeclared identifier 'nvvm_arch_t'
@codegen extern const nvvm_arch_t __nvvm_arch; 
                      ^

error: target declarations:20:23
undeclared identifier 'amdgpu_arch_t'
@codegen extern const amdgpu_arch_t __amdgpu_arch; 
                      ^

hello.c:

#include <stdio.h>

int main(int argc, char *argv[]) {
	printf("Hello !\n");
	return 0;
}

If we change the extension to '.cpp' then it compiles fine.

[johnsonjh]

@seanbaxter I've also experienced this same problem, but instead I patched the binary to get around the issue (but most likely breaking CUDA, which is fine for my test purpose.)

@mingodad You can workaround this by using -x=c++ but this has side effects, of course, see output of diff -U0 <(./circle -x=c -E -dM /dev/null) <(./circle -x=c++ -E -dM /dev/null) just to start.

Here's the fast hack I used to get plain C working with the distributed Build 200 binary:

$ radiff2 ./circle.orig ./circle
0x02849a10 636c617373 => 2020202020 0x02849a10
0x02849a30 636c617373 => 2020202020 0x02849a30
0x02849bf9 4063 => 2f2f 0x02849bf9
0x02849c57 4063 => 2f2f 0x02849c57

[brdjns]

In addition to @johnsonjh's answer, one can also use -xc++, similarly to GCC, Clang, et al.

[mingodad]

Thank you for all your suggestions ! Another way is to create a wrapper and include the C files: cppwrapper.cpp:

extern "C" {
#include "cfile";
}