track C++ memory allocations

Question

I am looking for a way to track memory allocations in a C++ program. I am not interested in memory leaks, which seem to be what most tools are trying to find, but r

Answer 1

For a generic C++ memory tracker you will need to overload the following:

global operator new
global operator new []
global operator delete
global operator delete []
any class allocators
any in-place allocators

The tricky bit is getting useful information, the overloaded operators only have size information for allocators and memory pointers for deletes. One answer is to use macros. I know. Nasty. An example - place in a header which is included from all source files:

#undef new

void *operator new (size_t size, char *file, int line, char *function);
// other operators

#define new new (__FILE__, __LINE__, __FUNCTION__)

and create a source file with:

void *operator new (size_t size, char *file, int line, char *function)
{
  // add tracking code here...
  return malloc (size);
}

The above only works if you don't have any operator new defined at class scope. If you do have some at class scope, do:

#define NEW new (__FILE__, __LINE__, __FUNCTION__)

and replace 'new type' with 'NEW type', but that requires changing a lot of code potentially.

As it's a macro, removing the memory tracker is quite straightforward, the header becomes:

#if defined ENABLED_MEMORY_TRACKER
#undef new

void *operator new (size_t size, char *file, int line, char *function);
// other operators

#define NEW new (__FILE__, __LINE__, __FUNCTION__)
#else
#define NEW new
#endif

and the implementation file:

#if defined ENABLED_MEMORY_TRACKER
void *operator new (size_t size, char *file, int line, char *function)
{
  // add tracking code here...
  return malloc (size);
}
endif