Cambio de comportamiento con scanf?

[enrieto]

Hola; una mirada al estándar [URL="http://port70.net/~nsz/c/c11/n1570.html#7.21.6.4"]C11[/URL] (clic para ver) nos dice que

3 The scanf function returns the value of the macro EOF if an input failure occurs before the first conversion (if any) has completed. Otherwise, the scanf function returns the number of input items assigned, which can be fewer than provided for, or even zero, in the event of an early matching failure.

Un ejemplo para estos casos puede ser:

Código C:

#include <stdio.h>
#include <stdlib.h>
 
int main()
{
    int n;
 
    int res = scanf("%d", &n);
 
    if(res == 0)
        printf("matching failure\n");
 
    if(ferror(stdin))
        perror("error");
 
    if(feof(stdin))
        printf("end-of-file reached.\n"); // Ctrl+Z en Windows
 
    printf("\n%d", n);
 
    return 0;
}