C++ new operator - memory layout

Question

Is the new operator guaranteed to allocate a continuous chunk of heap memory? I.e. is

objects=new Base[1024];

in terms of memory allocation the same as

objects=(Base*)malloc(1024*sizeof(base));

or can there be gaps?

Answer 1

Yes, the memory will be continuous. In terms of allocation, it's the same as the malloc version, but there are several differences (calls to constructor, new doesn't return NULL, malloc doesn't throw exceptions, etc.`).

Note that you can't mix up new[] with delete or free, you have to use delete[] objects to free the memory.

Answer 2

Maybe. The new operator does two things: it calls the operator new function, which will return a contiguous block of memory, adequately aligned for all possible types (except when it doesn't; e.g. a misused placement new); it then calls the constructor of the object, which can do just about anything. Including allocating additional blocks, which will not be contiguous with the first.