1 /* struct timeval subtraction.
2 Copyright (C) 1991-2012 Free Software Foundation, Inc.
4 This program is free software; you can redistribute it and/or
5 modify it under the terms of the GNU General Public License
6 as published by the Free Software Foundation; either version 2
7 of the License, or (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, if not, see <http://www.gnu.org/licenses/>.
18 /* Subtract the `struct timeval' values X and Y,
19 storing the result in RESULT.
20 Return 1 if the difference is negative, otherwise 0. */
23 timeval_subtract (result
, x
, y
)
24 struct timeval
*result
, *x
, *y
;
26 /* Perform the carry for the later subtraction by updating @var{y}. */
27 if (x
->tv_usec
< y
->tv_usec
) {
28 int nsec
= (y
->tv_usec
- x
->tv_usec
) / 1000000 + 1;
29 y
->tv_usec
-= 1000000 * nsec
;
32 if (x
->tv_usec
- y
->tv_usec
> 1000000) {
33 int nsec
= (x
->tv_usec
- y
->tv_usec
) / 1000000;
34 y
->tv_usec
+= 1000000 * nsec
;
38 /* Compute the time remaining to wait.
39 @code{tv_usec} is certainly positive. */
40 result
->tv_sec
= x
->tv_sec
- y
->tv_sec
;
41 result
->tv_usec
= x
->tv_usec
- y
->tv_usec
;
43 /* Return 1 if result is negative. */
44 return x
->tv_sec
< y
->tv_sec
;