No, that's just wrong. It becomes your responsibility to ensure your syscalls match and are available on the kernel you're actually running on which you may be

No, that's just wrong. It becomes your responsibility to ensure your syscalls match and are available on the kernel you're actually running on which you may be confusing with "not allowed to use". And very nearly all of the time this is a complete waste of everyone's time since the syscalls are a direct mirror of what's in libc anyway just with libc doing the compatibility for you. But just to really prove that you can absolutely syscall on Android, one of the largest, most widely deployed & shipped NDK/SDK apps does it to workaround a missing futimes in bionic: https://cs.chromium.org/chromium/src/base/os_compat_android.cc https://cs.chromium.org/chromium/src/base/os_compat_android....