title: malloc_size alternative on Linux and Windows
body: <p>How can one tell, given a <code>void *</code> pointer, what is the size of a block allocated on this given address (previously allocated using <code>malloc</code>; in Linux and Windows)? I hope both systems surely store this kind of information somewhere. That is, alternative of <code>malloc_size</code> which exists on OSX/Darwin. Using gcc/mingw if it helps.</p>