why is char's sign-ness not defined in C?

Question

The C standard states:

ISO/IEC 9899:1999, 6.2.5.15 (p. 49)

The three types char, signed char, and unsigned char are collectively called th

Answer 1

Perhaps historically some implementations' "char" were signed and some were unsigned, and so to be compatible with both they couldn't define it as one or the other.