Visual Studio 2010 C++: Get size of memory block allocated by malloc

Question

How can I get, given a pointer to a block of memory allocated with malloc, the size of it?

For example:

void* ptr = malloc( 10 ); //Allocate 10 bytes
printf( "%d", GetMemSize( ptr ) ); //Should print 10

I want to do this for debugging purposes.

Answer 1

In Visual C++ you can use _msize() for that.