?? lat_signal.c
字號:
#include "unpipc.h"
static int counter, nloop;
static pid_t childpid, parentpid;
void
sig_usr1(int signo)
{
Kill(parentpid, SIGUSR2); /* child receives USR1, sends USR2 */
return;
}
void
sig_usr2(int signo)
{
if (++counter < nloop)
Kill(childpid, SIGUSR1); /* parent receives USR2, sends USR1 */
else
Kill(parentpid, SIGTERM); /* parent terminates below */
return;
}
void
sig_term(int signo)
{
printf("latency: %.3f usec\n", Stop_time() / nloop);
Kill(childpid, SIGTERM);
exit(0);
}
int
main(int argc, char **argv)
{
if (argc != 2)
err_quit("usage: lat_signal <#loops>");
nloop = atoi(argv[1]);
counter = 0;
parentpid = getpid();
Signal(SIGUSR1, sig_usr1); /* for child */
Signal(SIGUSR2, sig_usr2); /* for parent */
if ( (childpid = Fork()) == 0) {
for ( ; ; ) { /* child */
pause();
}
exit(0); /* never reached */
}
/* 4parent */
Signal(SIGTERM, sig_term); /* for parent only */
Start_time();
Kill(childpid, SIGUSR1);
for ( ; ; )
pause();
}
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