Character handling functions -- Jan 88, dpANS

[Doug Gwyn]

In article <6192 at dhw68k.cts.com> david at dhw68k.cts.com (David H. Wolfskill) writes:
>1)	It would seem to be possible for a character -- interpreted in a
>	locale other than the "C" locale -- to cause isalpha to return
>	true, yet cause both isupper and islower to fail to return true.

Yes, this is right.  Not all character sets have a meaningful concept
of "case".  (Consider Chinese.)  Instead of arbitrarily picking either
lower or upper (or both), the implementor can simply tell the truth.

>2)	Similarly, it would seem to be possible for a character to be
>	able to cause isalpha to fail to return true, and yet cause
>	either (or both!) of isupper and islower to return true.

No, read the specification of isalpha again.  islower => isalpha
and  isupper => isalpha  but not the converse.