Release size in C ++: What is the correct behavior of the global delete operator (void * ptr, std :: size_t size)

Question

Release size in C ++: What is the correct behavior of the global delete operator (void * ptr, std :: size_t size)

I'm not sure if I understood the "size of release" in C ++ correctly. In C ++ 14, the following signature has been added to the global scope:

void operator delete(void* ptr, std::size_t size) noexcept

I am using GCC 7.1.0 to compile the following source:

#include <cstdio>   // printf()
#include <cstdlib>  // exit(),malloc(),free()
#include <new>      // new(),delete()

void* operator new(std::size_t size)
{
    std::printf("-> operator ::new(std::size_t %zu)\n", size);
    return malloc(size);
}

void operator delete(void* ptr) noexcept
{
    std::printf("-> operator ::delete(void* %p)\n", ptr);
    free(ptr);
}

void operator delete(void* ptr, std::size_t size) noexcept
{
    std::printf("-> operator ::delete(void* %p, size_t %zu)\n", ptr, size);
    free(ptr);
}


struct B
{
    double d1;
    void* operator new(std::size_t size)
    {
        std::printf("-> operator B::new(std::size_t %zu)\n", size);
        return malloc(size);
    };

    void operator delete(void* ptr, std::size_t size)
    {
        std::printf("-> operator B::delete(void* %p, size_t %zu)\n", ptr, size);
        free(ptr);
    };

    virtual ~B()
    {
        std::printf("-> B::~B()");
    }
};


struct D : public B
{
    double d2;
    virtual ~D()
    {
        std::printf("-> D::~D()");
    }
};

int main()
{

    B *b21 = new B();
    delete b21;

    B *b22 = new D();
    delete b22;

    D *d21 = new D();
    delete d21;

    std::printf("*****************************\n");

    B *b11 = ::new B();
    ::delete b11;

    B *b12 = ::new D();
    ::delete b12;

    D *d11 = ::new D();
    ::delete d11;

    return 0;
}

And I get the following output:

-> operator B::new(std::size_t 16)
-> B::~B()-> operator B::delete(void* 0x16e3010, size_t 16)
-> operator B::new(std::size_t 24)
-> D::~D()-> B::~B()-> operator B::delete(void* 0x16e3010, size_t 24)
-> operator B::new(std::size_t 24)
-> D::~D()-> B::~B()-> operator B::delete(void* 0x16e3010, size_t 24)
*****************************
-> operator ::new(std::size_t 16)
-> B::~B()-> operator ::delete(void* 0x16e3010, size_t 16)
-> operator ::new(std::size_t 24)
-> D::~D()-> B::~B()-> operator ::delete(void* 0x16e3010, size_t 16)
-> operator ::new(std::size_t 24)
-> D::~D()-> B::~B()-> operator ::delete(void* 0x16e3010, size_t 24)

MS Visual Studio 2017 gives me the following result:

-> operator B::new(std::size_t 16)
-> B::~B()-> operator B::delete(void* 0081CDE0, size_t 16)
-> operator B::new(std::size_t 24)
-> D::~D()-> B::~B()-> operator B::delete(void* 00808868, size_t 24)
-> operator B::new(std::size_t 24)
-> D::~D()-> B::~B()-> operator B::delete(void* 00808868, size_t 24)
*****************************
-> operator ::new(std::size_t 16)
-> B::~B()-> operator ::delete(void* 0081CDE0, size_t 16)
-> operator ::new(std::size_t 24)
-> D::~D()-> B::~B()-> operator ::delete(void* 00808868, size_t 24)
-> operator ::new(std::size_t 24)
-> D::~D()-> B::~B()-> operator ::delete(void* 00808868, size_t 24)

And Clang 5.0 does not even cause a global release operator delete(just operator deletewith one parameter). As the TC mentioned in the comments section, Clan needs an additional parameter -fsized-deallocationfor size distribution, and the result will be the same as for GCC:

-> operator B::new(std::size_t 16)
-> B::~B()-> operator B::delete(void* 0x219b6c0, size_t 16)
-> operator B::new(std::size_t 24)
-> D::~D()-> B::~B()-> operator B::delete(void* 0x219b6c0, size_t 24)
-> operator B::new(std::size_t 24)
-> D::~D()-> B::~B()-> operator B::delete(void* 0x219b6c0, size_t 24)
*****************************
-> operator ::new(std::size_t 16)
-> B::~B()-> operator ::delete(void* 0x219b6c0, size_t 16)
-> operator ::new(std::size_t 24)
-> D::~D()-> B::~B()-> operator ::delete(void* 0x219b6c0, size_t 16)
-> operator ::new(std::size_t 24)
-> D::~D()-> B::~B()-> operator ::delete(void* 0x219b6c0, size_t 24)