[src/trunk]: src/usr.bin/sdiff sdiff: fix undefined behavior for ctype functions

[rillig <rillig%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/350b726e38d8
branches:  trunk
changeset: 1023143:350b726e38d8
user:      rillig <rillig%NetBSD.org@localhost>
date:      Fri Aug 27 17:38:57 2021 +0000

description:
sdiff: fix undefined behavior for ctype functions

lint says: warning: argument to 'function from <ctype.h>' must be cast
to 'unsigned char', not to 'int' [342]

diffstat:

 usr.bin/sdiff/sdiff.c |  10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

diffs (45 lines):

diff -r a6ad432a4215 -r 350b726e38d8 usr.bin/sdiff/sdiff.c
--- a/usr.bin/sdiff/sdiff.c     Fri Aug 27 17:36:37 2021 +0000
+++ b/usr.bin/sdiff/sdiff.c     Fri Aug 27 17:38:57 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: sdiff.c,v 1.2 2009/04/13 07:19:55 lukem Exp $  */
+/*     $NetBSD: sdiff.c,v 1.3 2021/08/27 17:38:57 rillig Exp $ */
 /*     $OpenBSD: sdiff.c,v 1.20 2006/09/19 05:52:23 otto Exp $ */
 
 /*
@@ -423,7 +423,7 @@
                const char *p;
 
                /* Skip leading whitespace. */
-               for (p = cmd; isspace((int)(*p)); ++p)
+               for (p = cmd; isspace((unsigned char)(*p)); ++p)
                        ;
 
                switch (*p) {
@@ -579,7 +579,7 @@
 
        p = line;
        /* Go to character after line number. */
-       while (isdigit((int)(*p)))
+       while (isdigit((unsigned char)(*p)))
                ++p;
        c = *p;
        *p++ = 0;
@@ -592,7 +592,7 @@
 
                q = p;
                /* Go to character after file2end. */
-               while (isdigit((int)(*p)))
+               while (isdigit((unsigned char)(*p)))
                        ++p;
                c = *p;
                *p++ = 0;
@@ -612,7 +612,7 @@
 
        q = p;
        /* Go to character after line number. */
-       while (isdigit((int)(*p)))
+       while (isdigit((unsigned char)(*p)))
                ++p;
        c = *p;
        *p++ = 0;