c++ - Why doesn't SIGINT handler work in my code?

Question

I need my command line application to wait for Ctrl-C in the main thread and then execute some deinitialization code and exit.

I tested this scenario with the following test program:

#include <unistd.h>
#include <signal.h>
#include <cstdlib>
#include <cstdio>
#include <cassert>

using namespace std;

void control_break_handler(int) { printf("\ncontrol_break_handler\n"); }

int main()
{
    printf("%s", "Before signal\n");

    int result = 0;

    struct sigaction sigact = {};
    result = sigemptyset(&sigact.sa_mask);
    assert(result == 0);
    sigact.sa_handler = &control_break_handler;
    sigact.sa_flags = 0;
    result = sigaction(SIGINT, &sigact, NULL);
    assert(result == 0);

    sigset_t set;
    result = sigemptyset(&set);
    assert(result == 0);
    result = sigaddset(&set, SIGINT);
    assert(result == 0);
    int sig;
    result = sigwait(&set, &sig);
    assert(result == 0);
    printf("\nsigwait returned %d, sig = %d\n", result, sig);

    sleep(10);

    return 0;
}

But it just prints

sigwait returned 0, sig = 2

after first Ctrl-C and the "control_break_handler" called only after the second Ctrl-C. How do I execute deinitialization code on first Ctrl-C? I use Ubuntu 13.04 x64.

EDIT: Ok, it seems I figured this out. I thrown away sigaction and added call to sigprocmask before sigwait. It seems to work just fine.