There is a pretty big difference between these two cases. In C, calls to malloc() are explicit. You implement malloc() in C by not calling malloc(). In GC'd

There is a pretty big difference between these two cases. In C, calls to malloc() are explicit. You implement malloc() in C by not calling malloc(). In GC'd languages, the language runtime calls the garbage collector implicitly. So you need some more clever way of ensuring that these implicit calls do not occur. You also need to ensure that no garbage is created that will leak without a GC.