> >The behavior on a standard Linux system (glibc 2.2) is as
> >described above on invalid errnos: "Unknown error x".
> Which is illegal according to SUSv3.
> SUSv3 requires that strerror() is thread-safe, so it cannot
> return a modified string.
Yeah, I was quoting from SUSv2, which says that it does not have
to be thread-safe. There's another interface, strerror_r (defined
in LSB) which is designed to be reentrant, so it seems to be legal
as currently implemented. At the moment, LSB is aligned with SUSv2,