From: Paul Eggert <eggert@cs.ucla.edu>
Date: Tue, 17 Jun 2025 16:53:58 +0000 (-0700)
Subject: boot-time: comment that it's for container not host
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=974cbbbd0610c09d35359dc3c7fdf07668885aec;p=thirdparty%2Fgnulib.git

boot-time: comment that it's for container not host

Comment that in Docker etc., get_boot_time returns the
boot time of the container, not of its host.
Also, give an example file instead of saying just “FILE”.
---

diff --git a/lib/boot-time.h b/lib/boot-time.h
index 195839a2c5..7abfa12e44 100644
--- a/lib/boot-time.h
+++ b/lib/boot-time.h
@@ -29,11 +29,16 @@ extern "C" {
 /* Store the approximate time when the machine last booted in *P_BOOT_TIME,
    and return 0.  If it cannot be determined, return -1.
 
+   If the machine is a container inside another host machine,
+   return the boot time of the container, not the host.
+   The difference can matter in GNU/Linux, where times in /proc/stat
+   might be relative to boot time of the host, not the container.
+
    This function is not multithread-safe, since on many platforms it
-   invokes the functions setutxent, getutxent, endutxent.  These
-   functions are needed because they may lock FILE (so that we don't
-   read garbage when a concurrent process writes to FILE), but their
-   drawback is that they have a common global state.  */
+   invokes the functions setutxent, getutxent, endutxent.
+   These functions may lock a file like /var/log/wtmp (so that we
+   don't read garbage when a concurrent process writes to that file),
+   but their drawback is that they have a common global state.  */
 extern int get_boot_time (struct timespec *p_boot_time);