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

in those good old days C was defined, the character world was 7bit, so the sign-bit could be used for other things (like EOF)