GCC Warns About Function Pointer to Object Pointer Cast - c++

Question

Clearly casting between function pointers and object pointers is undefined behaviour in the general sense, but POSIX (see: dlsym) and WinAPI (see: GetProcAddress) require this.
Given this, and given the fact that such code is targeting a platform-specific API anyway, its portability to platforms where function pointers and object pointers aren't compatible is really irrelevant.
But -Wpedantic warns about it anyway, and #pragma GCC diagnostic ignored "-Wpedantic" has no effect:
warning: ISO C++ forbids casting between pointer-to-function and pointer-to-object [enabled by default]
I want to keep -Wpedantic enabled, since it does give good warnings, but I don't want to have real warnings and errors lost amidst a sea of irrelevant warnings about function pointer to object pointer casts.
Is there a way to accomplish this?
Running GCC 4.8.0 on Windows (MinGW):
gcc (rubenvb-4.8.0) 4.8.0
CODE SAMPLE
#include <windows.h>
#include <iostream>
int main (void) {
std::cout << *reinterpret_cast<int *>(GetProcAddress(LoadLibraryA("test.dll"),"five")) << std::endl;
}
Emits (with -Wpedantic):
warning_demo.cpp: In function 'int main()':
warning_demo.cpp:7:87: warning: ISO C++ forbids casting between pointer-to-funct
ion and pointer-to-object [enabled by default]
std::cout << *reinterpret_cast<int *>(GetProcAddress(LoadLibraryA("test.dll"),
"five")) << std::endl;
^

Answer 1

I think you could use g++'s system_header directive here:
wrap_GetProcAddress.h:
#ifndef wrap_GetProcAddress_included
#define wrap_GetProcAddress_included
#pragma GCC system_header
template <typename Result>
Result GetProcAddressAs( [normal parameters] )
{
return reinterpret_cast<Result>(GetProcAddressAs( [normal parameters] ));
}
#endif

Answer 2

This works fine.
template <typename RESULT, typename ...ARGS>
void * make_void_ptr(RESULT (*p)(ARGS...)) {
static_assert(sizeof(void *) == sizeof(void (*)(void)),
"object pointer and function pointer sizes must equal");
void *q = &p;
return *static_cast<void **>(q);
}

Answer 3

There's always the memcpy trick you can use:
int (*f)() = 0;
int *o;
memcpy(&o, &f, sizeof(int*));
You can see it on ideone: m is generating warnings, while g is OK.
As to other course of action you might want to take: One obvious possibility would be to "fix" the header defining dlsym to actually return a function pointer (like void (*)()). Good luck with that.