49 lines
915 B
C
49 lines
915 B
C
#include <signal.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <stdio.h>
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static void sig_int(int);
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int main(void) {
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sigset_t newmask, oldmask, waitmask;
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printf("program start\n");
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if(signal(SIGINT, sig_int) == SIG_ERR) {
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printf("signal(SIGINT) error\n");
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return -1;
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}
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sigemptyset(&waitmask);
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sigaddset(&waitmask, SIGUSR1);
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sigemptyset(&newmask);
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sigaddset(&newmask, SIGINT);
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if(sigprocmask(SIG_BLOCK, &newmask, &oldmask) < 0) {
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printf("SIG_BLOCK error\n");
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return -1;
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}
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printf("in critical region\n");
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if(sigsuspend(&waitmask) != -1) {
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printf("sigsuspend error\n");
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return -1;
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}
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printf("after return from sigsuspend\n");
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if(sigprocmask(SIG_SETMASK, &oldmask, NULL) < 0){
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printf("SIG_SETMASK error\n");
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return -1;
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}
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printf("program exit\n");
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return 0;
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}
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static void sig_int(int signo) {
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printf("caught sigint = %d\n", signo);
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}
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