What are the Windows and Linux native OS/system calls made from malloc()?

Question

I recently saw the following post:

A memory allocator isn\'t lower level than malloc. (The default allocator typically calls malloc directly or indi

Answer 1

On Windows, malloc implementations will usally call the win32 heap functions like HeapCreate, HeapDestroy, HeapAlloc, HeapFree. Those functions will call the NTDLL usermode heap manager located within ntdll.dll, those functions will have the RtlxxxHeap name, RtlAllocateHeap, RtlCreateHeap, etc...

In the end system calls within the NtxxxVirtualMemory group will be called, NtAllocateVirtualMemory, NtQueryVirtualMemory, NtFreeVirtualMemory.