I think found a bug in MSVC++. Or maybe this is a lack of my knowledge and I missed something in the code. I created a custom allocator:
#include <forward_list>
#include <iostream>
template <class T>
class Allocator
{
public:
typedef std::size_t size_type;
typedef std::ptrdiff_t difference_type;
typedef T *pointer;
typedef const T *const_pointer;
typedef T &reference;
typedef const T &const_reference;
typedef T value_type;
template <class U>
struct rebind
{
typedef Allocator<U> other;
};
Allocator()
{
std::cout << (ptrdiff_t) this << " Allocator()" << std::endl;
}
Allocator(const Allocator &allocator)
{
std::cout << (ptrdiff_t) this << " Allocator(const Allocator &allocator)" << std::endl;
}
template <class U>
Allocator(const Allocator<U> &other)
{
std::cout << (ptrdiff_t) this << " Allocator(const Allocator<U> &other)" << std::endl;
}
~Allocator()
{
std::cout << (ptrdiff_t) this << " ~Allocator()" << std::endl;
}
pointer allocate(size_type n, std::allocator<void>::const_pointer hint = 0)
{
std::cout << (ptrdiff_t) this << " allocate()" << std::endl;
return (pointer) std::malloc(n * sizeof(T));
}
void deallocate(pointer p, size_type n)
{
std::cout << (ptrdiff_t) this << " deallocate()" << std::endl;
std::free(p);
}
void construct(pointer p, const_reference val)
{
new (p) T(val);
}
void destroy(pointer p)
{
p->~T();
}
};
When I tried to use it for example this way:
Allocator<int> allocator;
std::forward_list<int, Allocator<int>> memoryPoolList(allocator);
I got following a output
557863138612 Allocator()
557863138648 Allocator(const Allocator<U> &other)
557863137412 Allocator(const Allocator<U> &other)
557863137412 allocate()
557863137412 ~Allocator()
557863137460 Allocator(const Allocator<U> &other)
557863137460 deallocate()
557863137460 ~Allocator()
557863138648 ~Allocator()
557863138612 ~Allocator()
If you look carefully allocate function is called on different object and deallocate() on another! Moreover why do they perform allocation on empty forward_list? This behaves this way for other containers too. And works pretty well on GCC. I'll be thankful for all ideas!
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