Both the glibc and the Microsoft CRT provide malloc hooks. I am working on automatic interfacing between C++ and JavaScript (SWIG JavaScript) and Node.js - as most other GC languages - tracks the heap size. When the C++ code allocates memory, this must be signalled to the GC which must be aware of the amount of free heap memory. For hand-written code it is usually not a problem, but the troubles start when the C++ code uses third party libraries. I am currently maintaining GDAL for JavaScript, ImageMagick for JavaScript and ffmpeg for JavaScript - and this is a huge problem in all three libraries. I want to make a cross-platform open source library that tracks heap memory usage and currently the only OS that is missing is macOS. Many other GCed languages need this library - including Java and Python. Any ideas if this is possible on macOS?