Unimplemented system call

[valdis.kletnieks at vt.edu]

On Tue, 05 Mar 2019 19:52:13 -0500, Umair Khan said:

> I was just wondering why are these system calls not implemented?

Ah. So now we get to the question you *should* have asked. :)

Depends on the system call and the hardware and the kernel config.
Often, on embedded systems, you know from the start that your system
won't be needed certain optional features, so you can build the kernel
without those features to save space.

However, if some program tries to issue a syscall that's related to those
optional features, you have to return *some* sort of error. So 'not implemented'
it is