Placement Syntax - Functions

Functions

The placement new functions are overloads of the non-placement new functions. The declaration of the non-placement new functions, for non-array and array new expressions respectively, are:

void * operator new (std::size_t) throw(std::bad_alloc);
void * operator new (std::size_t) throw(std::bad_alloc);

The Standard C++ library provides two placement overloads each for these functions. Their declarations are:

void * operator new (std::size_t, const std::nothrow_t &) throw;
void * operator new (std::size_t, void *) throw;
void * operator new (std::size_t, const std::nothrow_t &) throw;
void * operator new (std::size_t, void *) throw;

In all of the overloads, the first parameter to the operator new function is of type std::size_t, which when the function is called will be passed as an argument the amount of memory, in bytes, to allocate. All of the functions must return type void *, which is a pointer to the storage that the function allocates.

There are also placement delete functions. They are overloaded versions of the non-placement delete functions. The non-placement delete functions are declared as:

void operator delete (void *) throw;
void operator delete (void *) throw;

The Standard C++ library provides two placement overloads each for these functions. Their declarations are:

void operator delete (void *, const std::nothrow_t &) throw;
void operator delete (void *, void *) throw;
void operator delete (void *, const std::nothrow_t &) throw;
void operator delete (void *, void *) throw;

In all of the overloads, the first parameter to the operator delete function is of type void *, which is the address of the storage to deallocate.

For both the new and the delete functions, the functions are global, are not in any namespace, and do not have static linkage.