test.c

#include <sys/types.h>
#include <sys/uio.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <assert.h>

static void interrupted(int s) {
    write(1, "interrupted\n", 12);
}

int main() {
    char c[256];
    errno = 0;
    assert(!signal(SIGINT, interrupted));
    ssize_t r = read(0, c, sizeof(c));
    printf("r=%zd errno=%d (%s)\n", r, errno, strerror(errno));
}