operator new in custom namespace

[dirk]

Why doesn't the standard allow to overload operator new/delete in my
namespace, e.g.

namespace Foo
{
void* operator new( std::size_t sz );
void operator delete( void* address );
}

On the other hand I can overload new/delete per class:

class Foo1
{

static void* operator new( std::size_t sz );
static void operator delete( void* address );

};

And finally what happens if I have classes A and B that overwrite new
and delete and a class C that now inherits from both. What is the
expected behaviour there?



Cheers,
-Dirk

 

[Victor Bazarov]

Why doesn't the standard allow to overload operator new/delete in my
namespace, e.g.

namespace Foo
{
void* operator new( std::size_t sz );
void operator delete( void* address );
}

On the other hand I can overload new/delete per class:

class Foo1
{

static void* operator new( std::size_t sz );
static void operator delete( void* address );

'static' is implicit here, IIUIC. IOW, you don't need to use the
keyword in the function declaration.

};

And finally what happens if I have classes A and B that overwrite new
and delete and a class C that now inherits from both. What is the
expected behaviour there?

Not sure what having operator new in its own namespace would do. The
language says that if a class has operator new overloaded, then the
operator is used to allocate memory when constructing a dynamic object
of that class (chosen over the global operator new). What are you
trying to accomplish with the overloaded operator new in a namespace?

V

 

[James Kanze]

Why doesn't the standard allow to overload operator new/delete in my
namespace, e.g.

namespace Foo
{
void* operator new( std::size_t sz );
void operator delete( void* address );
}

Historical reasons, I would imagine.

On the other hand I can overload new/delete per class:

class Foo1
{
static void* operator new( std::size_t sz );
static void operator delete( void* address );
};

And finally what happens if I have classes A and B that overwrite new
and delete and a class C that now inherits from both. What is the
expected behaviour there?

Ambiguous. The compiler should complain.