> In the Linux world, since syscalls are exposed by libc, other non-C runtimes (for example, Go) end up needing to make system calls on their own without the li

> In the Linux world, since syscalls are exposed by libc, other non-C runtimes (for example, Go) end up needing to make system calls on their own without the libc wrappers. Is such a system just not a thing in Windows? Yeah, it's not a thing. You just import functions from ntdll the same way you import from anything else. The OS program loader reads your program's import table and loads them for you. > does ntdll expose any other functionality? Functionality that may want to be overridden by a different implementation, etc? It exposes lots of other stuff (DLL loading, memory heap, etc.) that you may want to do differently, but you can hook those at runtime if you really want to. It's not as convenient as just linking another library, but on the other hand, it makes it easier to replace them at runtime instead of at compile-time -- say, if you want a shared library to override a syscall.