This is the mail archive of the
mailing list for the glibc project.
Re: Are ut_user and ut_host in struct utmp NUL-terminated?
On 08/21/2018 10:47 AM, Michael Kerrisk (man-pages) wrote:
On 08/13/2018 02:10 PM, Florian Weimer wrote:
Can ut_user be exactly UT_NAMESIZE bytes long? Or is it necessary to
set aside a byte with the NUL terminator?
I'm not sure what POSIX says about struct utmpx. It never says “string”
in the context of ut_user, so I don't think it clarifies this matter.
Each of the char fields in utmp/utmpx can be completely filled with
characters. (I.e., there may not be a terminating null byte.)
As you note, POSIX does not say much here, but perhaps the fact that
the term "string" is not mentioned is a clue.
And indeed we already use __attribute__ ((__nonstring__)) for those. I
should have checked the current sources.