#include <stdio.h>
#include <signal.h>

static void nop(int unused) { }

int
main(void) {
    struct sigaction sa, osa;
    sigset_t mask;

    sigemptyset(&sa.sa_mask);
    sigemptyset(&osa.sa_mask);
    sa.sa_flags = 0;
    sa.sa_handler = nop;

    sigprocmask(0, NULL, &mask);
    printf("%dn", sigismember(&mask, SIGALRM));

    sigaction(SIGALRM, &sa, &osa);
    printf("%dn", sigismember(&osa.sa_mask, SIGALRM));
    printf("%dn", sigismember(&sa.sa_mask, SIGALRM));

    return 0;
}

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