diff options
Diffstat (limited to 'REORG.TODO/manual/examples/timeval_subtract.c')
-rw-r--r-- | REORG.TODO/manual/examples/timeval_subtract.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/REORG.TODO/manual/examples/timeval_subtract.c b/REORG.TODO/manual/examples/timeval_subtract.c new file mode 100644 index 0000000000..554dc77f40 --- /dev/null +++ b/REORG.TODO/manual/examples/timeval_subtract.c @@ -0,0 +1,44 @@ +/* struct timeval subtraction. + Copyright (C) 1991-2017 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License + as published by the Free Software Foundation; either version 2 + of the License, or (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, if not, see <http://www.gnu.org/licenses/>. +*/ + +/* Subtract the `struct timeval' values X and Y, + storing the result in RESULT. + Return 1 if the difference is negative, otherwise 0. */ + +int +timeval_subtract (struct timeval *result, struct timeval *x, struct timeval *y) +{ + /* Perform the carry for the later subtraction by updating @var{y}. */ + if (x->tv_usec < y->tv_usec) { + int nsec = (y->tv_usec - x->tv_usec) / 1000000 + 1; + y->tv_usec -= 1000000 * nsec; + y->tv_sec += nsec; + } + if (x->tv_usec - y->tv_usec > 1000000) { + int nsec = (x->tv_usec - y->tv_usec) / 1000000; + y->tv_usec += 1000000 * nsec; + y->tv_sec -= nsec; + } + + /* Compute the time remaining to wait. + @code{tv_usec} is certainly positive. */ + result->tv_sec = x->tv_sec - y->tv_sec; + result->tv_usec = x->tv_usec - y->tv_usec; + + /* Return 1 if result is negative. */ + return x->tv_sec < y->tv_sec; +} |