Package: libc6 Version: 2.28-10 Severity: important After hitting #932380 I looked at the source code of GNU screen, saw it uses the getutline(3) function, and compiled the example from its manpage.
The output is not what I expected: tglase@tglase:~ $ ./a.out before adding entry: tglase :0 2019-07-18 16:07 after adding entry: tglase :0 2019-07-18 16:07 after removing entry: tglase :0 2019-07-18 16:07 This is the same, no matter whether I’m in GNU screen in xterm, or just in xterm, or even on the Linux text console: tglase@tglase:~ $ ./a.out before adding entry: tglase tty2 2019-07-18 17:25 tglase :0 2019-07-18 16:07 after adding entry: tglase tty2 2019-07-18 17:25 tglase :0 2019-07-18 16:07 after removing entry: tglase tty2 2019-07-18 17:25 tglase :0 2019-07-18 16:07 utmp entries cannot be added (and the GNU screen source code contains curse^Wcomplaints about the GNU API for utmp lacking the ability to return success/error information, so the applications cannot even de‐ tect this!), while the file is set up correctly: tglase@tglase:~ $ ll /var/run/utmp -rw-r--r-- 1 root utmp 4608 Jul 18 17:26 /var/run/utmp tglase@tglase:~ $ w | cat 17:27:33 up 1:21, 1 user, load average: 1.35, 1.68, 2.12 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT tglase :0 - 16:07 ?xdm? 14:24 0.03s /usr/bin/ck-launch-session /usr/bin/monkeysphere-validation-agent /bin/mksh /usr/share/tarent/autokde.d/loadenv.sh icewm-session -- System Information: Debian Release: bullseye/sid APT prefers unreleased APT policy: (500, 'unreleased'), (500, 'buildd-unstable'), (500, 'unstable'), (100, 'experimental') Architecture: x32 (x86_64) Foreign Architectures: i386, amd64 Kernel: Linux 4.19.0-5-amd64 (SMP w/4 CPU cores) Kernel taint flags: TAINT_FIRMWARE_WORKAROUND Locale: LANG=C, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=C (charmap=UTF-8) Shell: /bin/sh linked to /bin/lksh Init: sysvinit (via /sbin/init)