| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | /* Copyright (C) 1991-2015 Free Software Foundation, Inc. |
| 2 | This file is part of the GNU C Library. |
| 3 | |
| 4 | The GNU C Library is free software; you can redistribute it and/or |
| 5 | modify it under the terms of the GNU Lesser General Public |
| 6 | License as published by the Free Software Foundation; either |
| 7 | version 2.1 of the License, or (at your option) any later version. |
| 8 | |
| 9 | The GNU C Library 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 GNU |
| 12 | Lesser General Public License for more details. |
| 13 | |
| 14 | You should have received a copy of the GNU Lesser General Public |
| 15 | License along with the GNU C Library; if not, see |
| 16 | <http://www.gnu.org/licenses/>. */ |
| 17 | |
| 18 | #include <unistd.h> |
| 19 | #include <sys/time.h> |
| 20 | |
| 21 | /* Schedule an alarm. In SECONDS seconds, the process will get a SIGALRM. |
| 22 | If SECONDS is zero, any currently scheduled alarm will be cancelled. |
| 23 | The function returns the number of seconds remaining until the last |
| 24 | alarm scheduled would have signaled, or zero if there wasn't one. |
| 25 | There is no return value to indicate an error, but you can set `errno' |
| 26 | to 0 and check its value after calling `alarm', and this might tell you. |
| 27 | The signal may come late due to processor scheduling. */ |
| 28 | unsigned int |
| 29 | alarm (seconds) |
| 30 | unsigned int seconds; |
| 31 | { |
| 32 | struct itimerval old, new; |
| 33 | unsigned int retval; |
| 34 | |
| 35 | new.it_interval.tv_usec = 0; |
| 36 | new.it_interval.tv_sec = 0; |
| 37 | new.it_value.tv_usec = 0; |
| 38 | new.it_value.tv_sec = (long int) seconds; |
| 39 | if (__setitimer (ITIMER_REAL, &new, &old) < 0) |
| 40 | return 0; |
| 41 | |
| 42 | retval = old.it_value.tv_sec; |
| 43 | /* Round to the nearest second, but never report zero seconds when |
| 44 | the alarm is still set. */ |
| 45 | if (old.it_value.tv_usec >= 500000 |
| 46 | || (retval == 0 && old.it_value.tv_usec > 0)) |
| 47 | ++retval; |
| 48 | return retval; |
| 49 | } |
| 50 | libc_hidden_def (alarm) |