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/* Signal Handlers that Return
Copyright (C) 1991-2021 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, see <https://www.gnu.org/licenses/>.
*/
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
/* This flag controls termination of the main loop. */
volatile sig_atomic_t keep_going = 1;
/* The signal handler just clears the flag and re-enables itself. */
void
catch_alarm (int sig)
{
keep_going = 0;
signal (sig, catch_alarm);
}
void
do_stuff (void)
{
puts ("Doing stuff while waiting for alarm....");
}
int
main (void)
{
/* Establish a handler for SIGALRM signals. */
signal (SIGALRM, catch_alarm);
/* Set an alarm to go off in a little while. */
alarm (2);
/* Check the flag once in a while to see when to quit. */
while (keep_going)
do_stuff ();
return EXIT_SUCCESS;
}
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