test.c

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

void sig_handler(int signo)
{
    printf("Signal %d", signo);
    exit(1);
}

int install_sig_handler(void)
{
    struct sigaction sa;

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

    if (sigaction(SIGTERM, &sa, NULL) != 0) {
        printf("sigaction(SIGTERM) error\n");
        return -1;
    }

    if (sigaction(SIGINT, &sa, NULL) != 0) {
        printf("sigaction(SIGINT) error\n");
        return -1;
    }

    if (sigaction(SIGKILL, &sa, NULL) != 0) {
        printf("sigaction(SIGKILL) error\n");
        return -1;
    }

    return 0;
}

int main(int argc, char const* argv[])
{
    install_sig_handler();

    while(1) {
        sleep(60);
    }

    return 0;
}

test.sh

#!/bin/bash

proc_term()
{
    echo "SIGTERM trapped"
    exit 1
}
trap "proc_term" SIGTERM

proc_kill()
{
    echo "SIGTERM trapped"
    exit 1
}
trap "proc_kill" SIGKILL

while true ; do
    sleep 60
done