diff --git a/lib/libedit/chared.c b/lib/libedit/chared.c
index 62e2f6a22219..b8acf510b412 100644
--- a/lib/libedit/chared.c
+++ b/lib/libedit/chared.c
@@ -148,7 +148,7 @@ protected int
 ce__isword(p)
     int p;
 {
-    return isalpha(p) || isdigit(p) || strchr("*?_-.[]~=", p) != NULL;
+    return isalpha((unsigned char) p) || isdigit((unsigned char) p) || strchr("*?_-.[]~=", p) != NULL;
 }
 
 
@@ -159,7 +159,7 @@ protected int
 cv__isword(p)
     int p;
 {
-    return !isspace(p);
+    return !isspace((unsigned char) p);
 }
 
 
diff --git a/lib/libedit/common.c b/lib/libedit/common.c
index c8be2b79ec44..a321c52cf11c 100644
--- a/lib/libedit/common.c
+++ b/lib/libedit/common.c
@@ -256,7 +256,7 @@ ed_move_to_beg(el, c)
 
     if (el->el_map.type == MAP_VI) {
         /* We want FIRST non space character */
-        while (isspace(*el->el_line.cursor))
+	while (isspace((unsigned char) *el->el_line.cursor))
 	    el->el_line.cursor++;
 	if (el->el_chared.c_vcmd.action & DELETE) {
 	    cv_delfini(el);
@@ -408,7 +408,7 @@ ed_digit(el, c)
     EditLine *el;
     int c;
 {
-    if (!isdigit(c))
+    if (!isdigit((unsigned char) c))
 	return CC_ERROR;
 
     if (el->el_state.doingarg) {
@@ -451,7 +451,7 @@ ed_argument_digit(el, c)
     EditLine *el;
     register int c;
 {
-    if (!isdigit(c))
+    if (!isdigit((unsigned char) c))
 	return CC_ERROR;
 
     if (el->el_state.doingarg) {
diff --git a/lib/libedit/emacs.c b/lib/libedit/emacs.c
index a3a19759f00c..d84c36022317 100644
--- a/lib/libedit/emacs.c
+++ b/lib/libedit/emacs.c
@@ -298,8 +298,8 @@ em_upper_case(el, c)
 		      el->el_state.argument, ce__isword);
 
     for (cp = el->el_line.cursor; cp < ep; cp++)
-	if (islower(*cp))
-	    *cp = toupper(*cp);
+	if (islower((unsigned char)*cp))
+	    *cp = toupper((unsigned char)*cp);
 
     el->el_line.cursor = ep;
     if (el->el_line.cursor > el->el_line.lastchar)
@@ -324,16 +324,16 @@ em_capitol_case(el, c)
 		      el->el_state.argument, ce__isword);
 
     for (cp = el->el_line.cursor; cp < ep; cp++) {
-	if (isalpha(*cp)) {
-	    if (islower(*cp))
-		*cp = toupper(*cp);
+	if (isalpha((unsigned char)*cp)) {
+	    if (islower((unsigned char)*cp))
+		*cp = toupper((unsigned char)*cp);
 	    cp++;
 	    break;
 	}
     }
     for (; cp < ep; cp++)
-	if (isupper(*cp))
-	    *cp = tolower(*cp);
+	if (isupper((unsigned char)*cp))
+	    *cp = tolower((unsigned char)*cp);
 
     el->el_line.cursor = ep;
     if (el->el_line.cursor > el->el_line.lastchar)
@@ -357,8 +357,8 @@ em_lower_case(el, c)
 		      el->el_state.argument, ce__isword);
 
     for (cp = el->el_line.cursor; cp < ep; cp++)
-	if (isupper(*cp))
-	    *cp = tolower(*cp);
+	if (isupper((unsigned char)*cp))
+	    *cp = tolower((unsigned char)*cp);
 
     el->el_line.cursor = ep;
     if (el->el_line.cursor > el->el_line.lastchar)
diff --git a/lib/libedit/key.c b/lib/libedit/key.c
index 302b6bd68d54..a84f413b5510 100644
--- a/lib/libedit/key.c
+++ b/lib/libedit/key.c
@@ -640,6 +640,8 @@ key__decode_char(buf, cnt, ch)
     char *buf;
     int   cnt, ch;
 {
+    ch &= 0xFF;
+
     if (ch == 0) {
 	buf[cnt++] = '^';
 	buf[cnt] = '@';
diff --git a/lib/libedit/refresh.c b/lib/libedit/refresh.c
index 6ad552283317..6fc8a562b6f5 100644
--- a/lib/libedit/refresh.c
+++ b/lib/libedit/refresh.c
@@ -43,7 +43,6 @@ static char sccsid[] = "@(#)refresh.c	8.1 (Berkeley) 6/4/93";
  */
 #include "sys.h"
 #include <stdio.h>
-#include <ctype.h>
 #include <unistd.h>
 #include <string.h>
 
@@ -98,6 +97,7 @@ re_addc(el, c)
     int c;
 {
     c &= 0xFF;
+
     if (isprint(c)) {
 	re_putc(el, c);
 	return;
diff --git a/lib/libedit/vi.c b/lib/libedit/vi.c
index 1a467809dd88..a9e6111993d9 100644
--- a/lib/libedit/vi.c
+++ b/lib/libedit/vi.c
@@ -277,7 +277,7 @@ vi_change_case(el, c)
     int c;
 {
     if (el->el_line.cursor < el->el_line.lastchar) {
-	c = *el->el_line.cursor;
+	c = *el->el_line.cursor & 0xFF;
 	if (isupper(c))
 	    *el->el_line.cursor++ = tolower(c);
 	else if (islower(c))