xref: /freebsd/share/man/man3/timeradd.3 (revision e5606f14a9b80d086b4f18a58ac08264860c6ad2)
1.\" Copyright (c) 1999 Kelly Yancey <kbyanc@posi.net>
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28.\"     $FreeBSD$
29.\"
30.Dd Aug 11, 1999
31.Dt TIMERADD 3
32.Os BSD 4
33.Sh NAME
34.Nm timeradd ,
35.Nm timersub ,
36.Nm timerclear ,
37.Nm timerisset ,
38.Nm timercmp
39.Nd operations on timevals
40.Sh SYNOPSIS
41.Fd #include <sys/time.h>
42.Fn timeradd "&tvp" "&uvp" "&vvp"
43.Fn timersub "&tvp" "&uvp" "&vvp"
44.Fn timerclear "&tvp"
45.Fn timerisset "&tvp"
46.Fn timercmp "&tvp" "&uvp" "cmp"
47.Sh DESCRIPTION
48.Pp
49These macros are provided for manipulating
50.Fa timeval
51structures for use with the
52.Fn gettimeofday
53and
54.Fn settimeofday
55calls.
56The structures pointed to by
57.Fa tvp ,
58.Fa uvp ,
59and
60.Fa vvp
61are defined in
62.Ao Pa sys/time.h Ac
63as:
64.Pp
65.Bd -literal
66struct timeval {
67	long	tv_sec;		/* seconds since Jan. 1, 1970 */
68	long	tv_usec;	/* and microseconds */
69};
70.Ed
71.Pp
72.Fn timeradd
73adds the time information stored in
74.Fa uvp
75to
76.Fa tvp
77and stores the resulting
78.Fa timeval
79in
80.Fa vvp .
81The results are simplified such that the value of
82.Fa vvp->tv_usec
83is always less than 1,000,000 (1 second).
84.Pp
85.Fn timersub
86subtracts the time information stored in
87.Fa uvp
88from
89.Fa tvp
90and stores the resulting
91.Fa timeval
92in
93.Fa vvp .
94.Pp
95.Fn timerclear
96initializes
97.Fa tvp
98to midnight (0 hour) January 1st, 1970 (the Epoch).
99.Pp
100.Fn timerisset
101returns true if
102.Fa tvp
103is set to any time value other than the Epoch.
104.Pp
105.Fn timercmp
106compares
107.Fa tvp
108to
109.Fa uvp
110using the comparison operator given in
111.Fa cmp
112and returns the result of that comparison.
113.Sh SEE ALSO
114.Xr gettimeofday 2
115.Sh HISTORY
116The
117.Fn timeradd
118family of macros were imported from
119.Nx 1.1 ,
120and appeared in
121.Fx 2.2.6 .
122