Small newlib C Library

You can use the small newlib library for a smaller code footprint, but there are naturally some disadvantages.

https://www.altera.com/content/dam/altera-www/global/en_US/pdfs/literature/hb/nios2/n2sw_nii5v2.pdf

So be careful if you are using one of such input routines.

// Nios II - Prog/main.c
#include "sys/alt_stdio.h"

while (1) {
    c = alt_getchar();
    alt_putchar(c);