C uint8_t and uint32_t signedness check

testsigns_uint.c

// NOTE: This file should NOT compile
// If it does, that means uint8_t and uint32_t are already defined without an include file...

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

// Test if char and int are signed or unsigned
int main() {
        // Char test
        printf("Is uint8_t signed? ");
        if ((uint8_t)-1 < 0)
                printf("YES, char is signed\n");
        else
                printf("NO, char is unsigned\n");
        // Int test
        printf("Is uint32_t signed? ");
        if ((uint32_t)-1 < 0)
                printf("YES, int is signed\n");
        else
                printf("NO, int is unsigned\n");
        // Print limits
        printf("CHAR_MIN is %i\n", CHAR_MIN);
        printf("INT_MIN is %i\n", INT_MIN);
        exit(0);
}