Reasons for supporting many platforms


For example, the C standards say that it is up to the compiler whether "char" is "signed char" or "unsigned char"

Consider this program:

    #include <stdio.h>
    int
    main()
    {
            char c = -1;
            printf("%d\n", (int)c);
            return 0;
    }
            char c = -1;
            printf("%d\n", (int)c);
            return 0;
    }

On ARM based platforms "char" is usually unsigned and a conversion of
(unsigned char)-1 to (int)-1 yields 255, not -1 as on other platforms