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author | rgrimes <rgrimes@FreeBSD.org> | 1994-05-27 05:00:24 +0000 |
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committer | rgrimes <rgrimes@FreeBSD.org> | 1994-05-27 05:00:24 +0000 |
commit | be22b15ae2ff8d7fe06b6e14fddf0c5b444a95da (patch) | |
tree | a18a706dffa5baf86a3b12bbfb4f81caa097f349 /lib/libc/sys/adjtime.2 | |
parent | 2a27bd86e6002c871e3b5561a5334653bb222a77 (diff) | |
download | FreeBSD-src-be22b15ae2ff8d7fe06b6e14fddf0c5b444a95da.zip FreeBSD-src-be22b15ae2ff8d7fe06b6e14fddf0c5b444a95da.tar.gz |
BSD 4.4 Lite Lib Sources
Diffstat (limited to 'lib/libc/sys/adjtime.2')
-rw-r--r-- | lib/libc/sys/adjtime.2 | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/lib/libc/sys/adjtime.2 b/lib/libc/sys/adjtime.2 new file mode 100644 index 0000000..84b9ad8 --- /dev/null +++ b/lib/libc/sys/adjtime.2 @@ -0,0 +1,111 @@ +.\" Copyright (c) 1980, 1991, 1993 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed by the University of +.\" California, Berkeley and its contributors. +.\" 4. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" @(#)adjtime.2 8.1 (Berkeley) 6/4/93 +.\" +.Dd June 4, 1993 +.Dt ADJTIME 2 +.Os BSD 4.3 +.Sh NAME +.Nm adjtime +.Nd "correct the time to allow synchronization of the system clock" +.Sh SYNOPSIS +.Fd #include <sys/time.h> +.Ft int +.Fn adjtime "struct timeval *delta" "struct timeval *olddelta" +.Sh DESCRIPTION +.Fn Adjtime +makes small adjustments to the system time, as returned by +.Xr gettimeofday 2 , +advancing or retarding it +by the time specified by the timeval +.Fa delta . +If +.Fa delta +is negative, the clock is +slowed down by incrementing it more slowly than normal until +the correction is complete. +If +.Fa delta +is positive, a larger increment than normal +is used. +The skew used to perform the correction is generally a fraction of one percent. +Thus, the time is always +a monotonically increasing function. +A time correction from an earlier call to +.Fn adjtime +may not be finished when +.Fn adjtime +is called again. +If +.Fa olddelta +is non-nil, +the structure pointed to will contain, upon return, the +number of microseconds still to be corrected +from the earlier call. +.Pp +This call may be used by time servers that synchronize the clocks +of computers in a local area network. +Such time servers would slow down the clocks of some machines +and speed up the clocks of others to bring them to the average network time. +.Pp +The call +.Fn adjtime +is restricted to the super-user. +.Sh RETURN VALUES +A return value of 0 indicates that the call succeeded. +A return value of -1 indicates that an error occurred, and in this +case an error code is stored in the global variable +.Va errno . +.Sh ERRORS +.Fn Adjtime +will fail if: +.Bl -tag -width Er +.It Bq Er EFAULT +An argument points outside the process's allocated address space. +.It Bq Er EPERM +The process's effective user ID is not that of the super-user. +.El +.Sh SEE ALSO +.Xr date 1 , +.Xr gettimeofday 2 , +.Xr timed 8 , +.Xr timedc 8 , +.Rs +.%T "TSP: The Time Synchronization Protocol for UNIX 4.3BSD" +.%A R. Gusella +.%A S. Zatti +.Re +.Sh HISTORY +The +.Nm +function call appeared in +.Bx 4.3 . |