Expand description of setdomainname() and getdomainname().
Note that getdomainname() is implemented as a library function
in glibc.
Note limits on size of domain name.
Reorganize ERRORS list.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Various pages use inconsistent terms for 'null byte' (which
is the C99/SUSv3 term for the '\0' character).
To rectify this the following changes were made in these pages:
Replace 'zero byte' with 'null byte'.
Replace 'null character' with 'null byte'.
Replace 'nulls' with 'null bytes'.
Replace 'NUL-terminated' by 'null-terminated'.
Replace 'NUL' by 'null byte'.
Replace 'terminating NUL' by 'terminating null byte'.
Replace 'final NUL' by 'terminating null byte'.
Replace 'NUL character' by 'null byte'.