diff options
Diffstat (limited to 'libc/sysdeps/unix/alarm.c')
-rw-r--r-- | libc/sysdeps/unix/alarm.c | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/libc/sysdeps/unix/alarm.c b/libc/sysdeps/unix/alarm.c new file mode 100644 index 000000000..84ab5a52f --- /dev/null +++ b/libc/sysdeps/unix/alarm.c @@ -0,0 +1,51 @@ +/* Copyright (C) 1991,1992,1994,1997,2002,2004 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <unistd.h> +#include <sys/time.h> + +/* Schedule an alarm. In SECONDS seconds, the process will get a SIGALRM. + If SECONDS is zero, any currently scheduled alarm will be cancelled. + The function returns the number of seconds remaining until the last + alarm scheduled would have signaled, or zero if there wasn't one. + There is no return value to indicate an error, but you can set `errno' + to 0 and check its value after calling `alarm', and this might tell you. + The signal may come late due to processor scheduling. */ +unsigned int +alarm (seconds) + unsigned int seconds; +{ + struct itimerval old, new; + unsigned int retval; + + new.it_interval.tv_usec = 0; + new.it_interval.tv_sec = 0; + new.it_value.tv_usec = 0; + new.it_value.tv_sec = (long int) seconds; + if (__setitimer (ITIMER_REAL, &new, &old) < 0) + return 0; + + retval = old.it_value.tv_sec; + /* Round to the nearest second, but never report zero seconds when + the alarm is still set. */ + if (old.it_value.tv_usec >= 500000 + || (retval == 0 && old.it_value.tv_usec > 0)) + ++retval; + return retval; +} +libc_hidden_def (alarm) |