CVS commit: src/usr.bin/xlint/lint1

["Roland Illig" <rillig%netbsd.org@localhost>]

Module Name:    src
Committed By:   rillig
Date:           Mon Apr  5 02:07:15 UTC 2021

Added Files:
        src/usr.bin/xlint/lint1: ckctype.c

Log Message:
lint: warn about for wrong type cast in argument to ctype.h functions

The argument to most of the functions from <ctype.h> "shall either be
representable as an 'unsigned char' or shall equal the value of the
macro EOF".

When confronted with the infamous warning 'array subscript has type
char', there are enough programmers who don't know the background of
that warning and thus fix it in a wrong way.  Neither GCC nor Clang
explain its warning to target these programmers.

Both GCC and Clang warn about 'array subscript has type char', but they
ignore the other requirements of the <ctype.h> functions, even though
these are in the C standard library.

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94182
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95177
https://stackoverflow.com/a/60696378


To generate a diff of this commit:
cvs rdiff -u -r0 -r1.1 src/usr.bin/xlint/lint1/ckctype.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.