62 lines
1.1 KiB
C
62 lines
1.1 KiB
C
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#include <signal.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <time.h>
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#include <errno.h>
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void catcher(int sig) {
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printf("Signal catcher called for signal %d\n", sig);
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}
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void timestamp(char *str) {
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time_t t;
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time(&t);
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printf("The time %s is %s\n", str, ctime(&t));
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}
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int main(int argc, char *argv[]) {
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int result = 0;
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int err = 0;
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struct sigaction sigact;
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sigset_t waitset;
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siginfo_t info;
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struct timespec timeout;
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sigemptyset(&sigact.sa_mask);
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sigact.sa_flags = 0;
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sigact.sa_handler = catcher;
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sigaction(SIGALRM, &sigact, NULL);
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sigemptyset(&waitset);
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sigaddset(&waitset, SIGALRM);
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sigprocmask(SIG_BLOCK, &waitset, NULL);
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timeout.tv_sec = 1; /* Number of seconds to wait */
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timeout.tv_nsec = 1000; /* Number of nanoseconds to wait */
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alarm(4);
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timestamp("before sigtimedwait()");
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result = sigtimedwait(&waitset, &info, &timeout);
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err = errno;
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timestamp("after sigtimedwait()");
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if(result > 0){
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printf("sigtimedwait() returned for signal %d\n", info.si_signo);
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return 1;
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}
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printf("sigtimedwait() returned %d; errno = %d\n", result, err);
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if(err != EAGAIN){
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perror("errno is not EAGAIN");
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return 2;
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}
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return 0;
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}
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