Public bug reported: When I compile and run the attached program, the output shows an inconsistency between the time returned by clock_gettime() and time(). Even though the call to time() is after the call to clock_gettime(), it can return an earlier timestamp. This is particularly apparent after waiting until a particular time, as shown in the example code. Sample output is:
Now (clock_gettime) time is 1574670740847614452 (timespec) =>1574670740(time_t) =>8:32:20 Now (time(nullptr)) time is 1574670740(time_t) =>8:32:20 Now (clock_gettime) time is 1574670742000185727 (timespec) =>1574670742(time_t) =>8:32:22 Now (time(nullptr)) time is 1574670741(time_t) =>8:32:21 Compiled with g++ v7 from the ubuntu repositories. Output of g++ version: g++ (Ubuntu 7.4.0-1ubuntu1~18.04.1) 7.4.0 Copyright (C) 2017 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: linux-image-4.15.0-1064-oem 4.15.0-1064.73 ProcVersionSignature: Ubuntu 4.15.0-1064.73-oem 4.15.18 Uname: Linux 4.15.0-1064-oem x86_64 ApportVersion: 2.20.9-0ubuntu7.9 Architecture: amd64 CurrentDesktop: ubuntu:GNOME Date: Mon Nov 25 08:28:21 2019 DistributionChannelDescriptor: # This is the distribution channel descriptor for the OEM CDs # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor canonical-oem-somerville-bionic-amd64-20180608-47+beaver-turtlebay+X57 InstallationDate: Installed on 2019-08-12 (104 days ago) InstallationMedia: Ubuntu 18.04 "Bionic" - Build amd64 LIVE Binary 20180608-09:38 ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_GB.UTF-8 SHELL=/bin/bash SourcePackage: linux-signed-oem UpgradeStatus: No upgrade log present (probably fresh install) ** Affects: linux-signed-oem (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug bionic ** Attachment added: "File showing inconsistency" https://bugs.launchpad.net/bugs/1853807/+attachment/5307635/+files/t2.cpp -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-signed-oem in Ubuntu. https://bugs.launchpad.net/bugs/1853807 Title: clock_gettime and time are inconsistent with each other Status in linux-signed-oem package in Ubuntu: New Bug description: When I compile and run the attached program, the output shows an inconsistency between the time returned by clock_gettime() and time(). Even though the call to time() is after the call to clock_gettime(), it can return an earlier timestamp. This is particularly apparent after waiting until a particular time, as shown in the example code. Sample output is: Now (clock_gettime) time is 1574670740847614452 (timespec) =>1574670740(time_t) =>8:32:20 Now (time(nullptr)) time is 1574670740(time_t) =>8:32:20 Now (clock_gettime) time is 1574670742000185727 (timespec) =>1574670742(time_t) =>8:32:22 Now (time(nullptr)) time is 1574670741(time_t) =>8:32:21 Compiled with g++ v7 from the ubuntu repositories. Output of g++ version: g++ (Ubuntu 7.4.0-1ubuntu1~18.04.1) 7.4.0 Copyright (C) 2017 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: linux-image-4.15.0-1064-oem 4.15.0-1064.73 ProcVersionSignature: Ubuntu 4.15.0-1064.73-oem 4.15.18 Uname: Linux 4.15.0-1064-oem x86_64 ApportVersion: 2.20.9-0ubuntu7.9 Architecture: amd64 CurrentDesktop: ubuntu:GNOME Date: Mon Nov 25 08:28:21 2019 DistributionChannelDescriptor: # This is the distribution channel descriptor for the OEM CDs # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor canonical-oem-somerville-bionic-amd64-20180608-47+beaver-turtlebay+X57 InstallationDate: Installed on 2019-08-12 (104 days ago) InstallationMedia: Ubuntu 18.04 "Bionic" - Build amd64 LIVE Binary 20180608-09:38 ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_GB.UTF-8 SHELL=/bin/bash SourcePackage: linux-signed-oem UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-signed-oem/+bug/1853807/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
