Sharpmake.FunctionalTests/FastBuildFunctionalTest/codebase/MixCppAndCExe/hello_c.c (3 lines of code) (raw):
#include <stdio.h>
#ifdef __cplusplus
#error This file mustn't be compiled as C++
#endif
void hello_c(void)
{
printf("Hello from C code!\n");
}