gcc/testsuite/gdc.test/compilable/dtoh_CPPNamespaceDeclaration.d

/*
REQUIRED_ARGS: -HC -c -o-
PERMUTE_ARGS:
TEST_OUTPUT:
---
// Automatically generated by Digital Mars D Compiler

#pragma once

#include <assert.h>
#include <math.h>
#include <stddef.h>
#include <stdint.h>

#ifdef CUSTOM_D_ARRAY_TYPE
#define _d_dynamicArray CUSTOM_D_ARRAY_TYPE
#else
/// Represents a D [] array
template<typename T>
struct _d_dynamicArray final
{
    size_t length;
    T *ptr;

    _d_dynamicArray() : length(0), ptr(NULL) { }

    _d_dynamicArray(size_t length_in, T *ptr_in)
        : length(length_in), ptr(ptr_in) { }

    T& operator[](const size_t idx) {
        assert(idx < length);
        return ptr[idx];
    }

    const T& operator[](const size_t idx) const {
        assert(idx < length);
        return ptr[idx];
    }
};
#endif

namespace nameSpace
{
    extern void fn();

    namespace nameSpace2
    {
        extern void fn2();

    }
    extern double identity(double _param_0);

}
---
*/

extern(C++, "nameSpace")
{
    void fn() {}

    extern(C++, nameSpace2)
    {
        void fn2() {}
    }

    double identity(double) { return _param_0; }
}