What signal am I receiving?

signal.c

#define _POSIX_C_SOURCE 1
#include <signal.h>
#include <sys/signalfd.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>


int main(void){
	sigset_t sig_mask;
	sigfillset(&sig_mask);
	if(sigprocmask(SIG_BLOCK, &sig_mask, NULL) == -1){
		perror("sigprocmask");
		exit(EXIT_FAILURE);
	}
	int sig_fd = signalfd(-1, &sig_mask, 0);
	if(sig_fd == -1){
		perror("signalfd");
		exit(EXIT_FAILURE);
	}
	struct signalfd_siginfo buffer;
	while(1){
		ssize_t rc = read(sig_fd, &buffer, sizeof(struct signalfd_siginfo));
		if(rc < 0){
			perror("read");
			exit(EXIT_FAILURE);
		}
		printf("Received signal #%d\n", buffer.ssi_signo);
		if(buffer.ssi_signo == SIGQUIT || buffer.ssi_signo == SIGINT){
			printf("That's all, folks.\n");
			exit(EXIT_SUCCESS);
		}
	}
}