hang.c

#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>

int main() {
    for (;;) {
        char buf[1];
        ssize_t r = read(STDIN_FILENO, buf, 1);
        if (r == 0) {
            break;
        } else if (r < 0) {
            perror("read");
            exit(1);
        } else {
            printf("%d\n", (int) buf[0]);
        }
    }
    return 0;
}