misc/59655: man pages report incorrect OS version when running later kernel

[rwhitlock22%gmail.com@localhost]

>Number:         59655
>Category:       misc
>Synopsis:       man pages report incorrect OS version when running later kernel
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    misc-bug-people
>State:          open
>Class:          doc-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Sep 14 16:20:00 +0000 2025
>Originator:     Robert Whitlock
>Release:        NetBSD 11.99.2 kernel with 10.99.14 userland
>Organization:
>Environment:
NetBSD thinkpad 11.99.2 NetBSD 11.99.2 (kerncompile) #0: Sat Sep 13 23:35:40 EDT 2025  rob@thinkpad:/usr/netbsd/current/build/THINKPAD/kerncompile amd64
>Description:
If update your kernel so that you are running a kernel that is newer than your userland then many man pages report an incorrect OS version for the OS that they were from. For instance, printf(3) reports that it is from version 11.99.2 if your kernel is 11.99.2, even though printf comes from libc, which is a userland library, and so should correspond to the version of the userland that was installed.

This seems to be because the man pages use the .Os directive with no further arguments to denote the OS version, which presumably uses the version of the kernel.
>How-To-Repeat:
Install NetBSD.
Compile a newer kernel.
Install the newer kernel and reboot.
man 3 printf
>Fix:
Add explicit version information to the .Os directives in the man pages. This should be parameterized so that the build resolves the arguments of .Os to be the version of the OS that is being built. After the man pages are built during the userland build, the OS version arguments for .Os would be plain text and so would not depend on the specific kernel version that is running.

Perhaps some thought could be given to the possibility of whether it would be desirable to avoid updating the version if the interface has not changed.