* Why is ostream ::operator<<  (unsigned char) not defined?
I do not know, but see below.

* Why is operator<<  (ostream, unsigned char) defined?
Because otherwise  operator>>  (istream, unsigned char&) would do the
wrong thing:
unsigned char const c ((25)); unsigned char d;
ostream<<  c; istream>>  d; // Oops, d == '2'

* Why does operator>>  (istream, unsigned char&) do the wrong thing?
Because at the time when it was defined, the C library did not provide
any method for reading a variable of type unsigned char.  This problem
was fixed in C99.  (Were it supported, this operator would have been
defined as a member function.)

* So why is operator>>  (istream, unsigned char&) defined?
I suppose that BS preferred having broken I/O to having no I/O in this case.

* Why is operator>>  (istream, unsigned char []) defined?
It is a logical consequence of having istream ::operator>>  (unsigned
char&) do the wrong thing.  This one is particularly illogical, since
neither ctype<  unsigned char>  nor char_traits<  unsigned char>  need
to exist.

* So why is istream ::read (unsigned [], streamsize) not defined?
This one, in contrast to the previous ones, would be useful for binary
I/O.  It may stem from the fact that at the time void did not exist, the
idiom for a raw pointer was char *, not unsigned char *, which would be
more appropriate, maybe because unsigned char is longer to type, and
typedef pointer was considered too trivial to define.

<URL: http://adrinael.net/wrong6>

Chris


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