Red Hat Bugzilla – Bug 735789
realtime clock functions need to link with -lrt
Last modified: 2013-02-21 05:45:21 EST
+++ This bug was initially created as a clone of Bug #734836 +++ Description of problem: The clock_gettime(2), clock_settime(2), clock_getres(2) and clock_nanosleep(2) man pages do not mention the fact that you must link to the librt library (with -lrt command line option) to use them. Without -lrt, the compile fails: $ gcc test.c /tmp/ccyoU0Vi.o: In function `getustime': test.c:(.text+0x36): undefined reference to `clock_gettime' collect2: ld returned 1 exit status The latest version of the man page in Fedora 15 does note this fact in the SYNOPSYS section: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SYNOPSIS #include <time.h> int clock_getres(clockid_t clk_id, struct timespec *res); int clock_gettime(clockid_t clk_id, struct timespec *tp); int clock_settime(clockid_t clk_id, const struct timespec *tp); Link with -lrt. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Please update the realtime clock function man pages to note the linking options. Version-Release number of selected component (if applicable): man-pages-3.22-17.el6.noarch How reproducible: every time Steps to Reproduce: 1. man clock_gettime Actual results: no mention of -lrt link option Expected results: note on linking with -lrt --- Additional comment from jbastian@redhat.com on 2011-08-31 11:25:10 EDT --- There's something strange with the RHEL 6 man pages: the upstream man-pages-3.22.tar.gz contains the linking notes and was written in 2009, but the RHEL 6 version of the man page is from 2004. --- Additional comment from jbastian@redhat.com on 2011-08-31 11:29:48 EDT --- The RHEL 6 man-pages-3.22-17.el6.src.rpm contains a man-pages_syscalls-01.tar.bz2 which overrides a number of the man pages including the clock_* pages with much older versions of the pages. Is this intentional? --- Additional comment from pschiffe@redhat.com on 2011-09-05 07:59:33 EDT --- man-pages_syscalls-01.tar.bz2 is from old BZ #159225, when not all man pages was included in upstream tarball. It should be revised and irrelevant man pages removed. For now, I'll fix four clock_* functions in MPO process in RHEL-6.2, rest when man-pages component will be updated in RHEL.
This request was evaluated by Red Hat Product Management for inclusion in the current release of Red Hat Enterprise Linux. Because the affected component is not scheduled to be updated in the current release, Red Hat is unfortunately unable to address this request at this time, but it has been proposed for the next release.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. http://rhn.redhat.com/errata/RHBA-2013-0447.html