Synopsis: gcc warns about subscripts of type char using tolower

State-Changed-From-To: open->closed
State-Changed-By: dsl@netbsd.org
State-Changed-When: Thu, 22 Sep 2005 20:39:24 +0000
State-Changed-Why:
This warning is deliberate (and may even be why gcc warns about indexing
arrays with 'char').  It's purpose is to generate warnings for badly written
code - which the definition of the isxxx() functions make very likely.
The issue is that the domain of the isxxx() functions is EOF and all the
values of 'unsigned char', so if you use a 'char' variable as the argument,
and it happens to be negative, then an incorrect value is returned (indeed
the program could easily core dump immediately).