From 7ea04c7f0fddcf36198ada66198fc65289b5dae7 Mon Sep 17 00:00:00 2001
From: Witold Filipczyk <witekfl@poczta.onet.pl>
Date: Tue, 28 Jun 2022 20:25:06 +0200
Subject: [PATCH] [isspace] Some implementations of isspace require unsigned
 char

---
 src/bfu/inpfield.c                 | 14 +++++-----
 src/bfu/text.c                     |  6 ++---
 src/bookmarks/backend/xbel.c       |  2 +-
 src/config/cmdline.c               |  2 +-
 src/config/conf.c                  |  4 +--
 src/config/options.c               |  8 +++---
 src/config/opttypes.c              |  2 +-
 src/cookies/parser.c               |  4 +--
 src/document/dom/source.c          |  4 +--
 src/document/html/parser.c         |  4 +--
 src/document/html/parser/forms.c   | 10 +++----
 src/document/html/parser/parse.c   | 42 +++++++++++++++---------------
 src/document/html/renderer.c       |  2 +-
 src/document/html/tables.c         | 12 ++++-----
 src/document/plain/renderer.c      |  2 +-
 src/document/xml/renderer2.c       | 14 +++++-----
 src/dom/configuration.c            |  2 +-
 src/dom/select.c                   |  4 +--
 src/mime/backend/mailcap.c         |  2 +-
 src/protocol/http/http_negotiate.c |  2 +-
 src/terminal/kbd.c                 |  4 +--
 src/util/file.c                    |  2 +-
 src/util/string.h                  |  4 +--
 src/viewer/text/form.c             | 14 +++++-----
 24 files changed, 83 insertions(+), 83 deletions(-)

diff --git a/src/bfu/inpfield.c b/src/bfu/inpfield.c
index d27d27c4..4133b8ba 100644
--- a/src/bfu/inpfield.c
+++ b/src/bfu/inpfield.c
@@ -601,9 +601,9 @@ kbd_field(struct dialog_data *dlg_data, struct widget_data *widget_data)
 				int cdata_len = strlen(widget_data->cdata);
 				int start = widget_data->info.field.cpos;
 
-				while (start > 0 && isspace(widget_data->cdata[start - 1]))
+				while (start > 0 && isspace((unsigned char)widget_data->cdata[start - 1]))
 					--start;
-				while (start > 0 && !isspace(widget_data->cdata[start - 1]))
+				while (start > 0 && !isspace((unsigned char)widget_data->cdata[start - 1]))
 					--start;
 
 				memmove(widget_data->cdata + start,
@@ -616,19 +616,19 @@ kbd_field(struct dialog_data *dlg_data, struct widget_data *widget_data)
 			}
 
 		case ACT_EDIT_MOVE_BACKWARD_WORD:
-			while (widget_data->info.field.cpos > 0 && isspace(widget_data->cdata[widget_data->info.field.cpos - 1]))
+			while (widget_data->info.field.cpos > 0 && isspace((unsigned char)widget_data->cdata[widget_data->info.field.cpos - 1]))
 				--widget_data->info.field.cpos;
-			while (widget_data->info.field.cpos > 0 && !isspace(widget_data->cdata[widget_data->info.field.cpos - 1]))
+			while (widget_data->info.field.cpos > 0 && !isspace((unsigned char)widget_data->cdata[widget_data->info.field.cpos - 1]))
 				--widget_data->info.field.cpos;
 
 			goto display_field;
 
 		case ACT_EDIT_MOVE_FORWARD_WORD:
-			while (isspace(widget_data->cdata[widget_data->info.field.cpos]))
+			while (isspace((unsigned char)widget_data->cdata[widget_data->info.field.cpos]))
 				++widget_data->info.field.cpos;
-			while (widget_data->cdata[widget_data->info.field.cpos] && !isspace(widget_data->cdata[widget_data->info.field.cpos]))
+			while (widget_data->cdata[widget_data->info.field.cpos] && !isspace((unsigned char)widget_data->cdata[widget_data->info.field.cpos]))
 				++widget_data->info.field.cpos;
-			while (isspace(widget_data->cdata[widget_data->info.field.cpos]))
+			while (isspace((unsigned char)widget_data->cdata[widget_data->info.field.cpos]))
 				++widget_data->info.field.cpos;
 
 			goto display_field;
diff --git a/src/bfu/text.c b/src/bfu/text.c
index 8fba9353..bf597216 100644
--- a/src/bfu/text.c
+++ b/src/bfu/text.c
@@ -20,7 +20,7 @@
 #include "util/color.h"
 
 /* FIXME: For UTF-8 strings we need better function than isspace. */
-#define is_unsplitable(pos) (*(pos) && *(pos) != '\n' && !isspace(*(pos)))
+#define is_unsplitable(pos) (*(pos) && *(pos) != '\n' && !isspace((unsigned char)*(pos)))
 
 void
 add_dlg_text(struct dialog *dlg, char *text,
@@ -175,7 +175,7 @@ split_lines(struct widget_data *widget_data, int max_width)
 		int cells = 0;
 
 		/* Skip first leading \n or space. */
-		if (isspace(*text)) text++;
+		if (isspace((unsigned char)*text)) text++;
 		if (!*text) break;
 
 #ifdef CONFIG_UTF8
@@ -230,7 +230,7 @@ dlg_format_text_do_node(struct dialog_data *dlg_data,
 		int cells = 0;
 
 		/* Skip first leading \n or space. */
-		if (!firstline && isspace(*text))
+		if (!firstline && isspace((unsigned char)*text))
 			text++;
 		else
 			firstline = 0;
diff --git a/src/bookmarks/backend/xbel.c b/src/bookmarks/backend/xbel.c
index e724da78..9d50834d 100644
--- a/src/bookmarks/backend/xbel.c
+++ b/src/bookmarks/backend/xbel.c
@@ -316,7 +316,7 @@ delete_whites(const char *s)
 		 * in section 2.3 of XML 1.1.  U+0085 and U+2028 need
 		 * not be recognized here because section 2.11 says
 		 * the XML processor must translate them to U+000A.
-		 * Do not use isspace() because the string is in UTF-8
+		 * Do not use isspace((unsigned char)) because the string is in UTF-8
 		 * and individual bytes might not be characters at
 		 * all.  */
 		switch (s[i]) {
diff --git a/src/config/cmdline.c b/src/config/cmdline.c
index ff9dff71..424bde6a 100644
--- a/src/config/cmdline.c
+++ b/src/config/cmdline.c
@@ -224,7 +224,7 @@ lookup_cmd(struct option *o, char ***argv, int *argc)
 }
 
 #define skipback_whitespace(start, S) \
-	while ((start) < (S) && isspace((S)[-1])) (S)--;
+	while ((start) < (S) && isspace((unsigned char)(S)[-1])) (S)--;
 
 enum remote_method_enum {
 	REMOTE_METHOD_OPENURL,
diff --git a/src/config/conf.c b/src/config/conf.c
index becfe499..818bafca 100644
--- a/src/config/conf.c
+++ b/src/config/conf.c
@@ -114,7 +114,7 @@ skip_white(struct conf_parsing_pos *pos)
 	char *start = pos->look;
 
 	while (*start) {
-		while (isspace(*start)) {
+		while (isspace((unsigned char)*start)) {
 			if (*start == '\n') {
 				pos->line++;
 			}
@@ -652,7 +652,7 @@ parse_config_command(struct option *options, struct conf_parsing_state *state,
 		int cmdlen = strlen(handler->command);
 
 		if (!strncmp(state->pos.look, handler->command, cmdlen)
-		    && isspace(state->pos.look[cmdlen])) {
+		    && isspace((unsigned char)state->pos.look[cmdlen])) {
 			enum parse_error err;
 
 			state->pos.look += cmdlen;
diff --git a/src/config/options.c b/src/config/options.c
index 051e5ff8..6fa69073 100644
--- a/src/config/options.c
+++ b/src/config/options.c
@@ -97,7 +97,7 @@ check_caption(char *caption)
 	if (!len) return;
 
 	c = caption[len - 1];
-	if (isspace(c) || bad_punct(c))
+	if (isspace((unsigned char)c) || bad_punct(c))
 		DBG("bad char at end of caption [%s]", caption);
 
 #ifdef CONFIG_NLS
@@ -106,7 +106,7 @@ check_caption(char *caption)
 	if (!len) return;
 
 	c = caption[len - 1];
-	if (isspace(c) || bad_punct(c))
+	if (isspace((unsigned char)c) || bad_punct(c))
 		DBG("bad char at end of i18n caption [%s]", caption);
 #endif
 }
@@ -125,7 +125,7 @@ check_description(char *desc)
 	if (!len) return;
 
 	c = desc[len - 1];
-	if (isspace(c))
+	if (isspace((unsigned char)c))
 		DBG("bad char at end of description [%s]", desc);
 
 #ifdef CONFIG_NLS
@@ -137,7 +137,7 @@ check_description(char *desc)
 		DBG("punctuation char possibly missing at end of i18n description [%s]", desc);
 
 	c = desc[len - 1];
-	if (isspace(c))
+	if (isspace((unsigned char)c))
 		DBG("bad char at end of i18n description [%s]", desc);
 #endif
 }
diff --git a/src/config/opttypes.c b/src/config/opttypes.c
index 8340d9c4..570bbfef 100644
--- a/src/config/opttypes.c
+++ b/src/config/opttypes.c
@@ -213,7 +213,7 @@ num_rd(struct option *opt, char **file, int *line)
 
 	/* Another trap for unwary - we need to check *end, not **file - reason
 	 * is left as an exercise to the reader. */
-	if ((*end != 0 && (commandline || (!isspace(*end) && *end != '#')))
+	if ((*end != 0 && (commandline || (!isspace((unsigned char)*end) && *end != '#')))
 	    || (*value < opt->min || *value > opt->max)) {
 		mem_free(value);
 		return NULL;
diff --git a/src/cookies/parser.c b/src/cookies/parser.c
index fe075deb..006d6415 100644
--- a/src/cookies/parser.c
+++ b/src/cookies/parser.c
@@ -45,7 +45,7 @@ parse_cookie_str(struct cookie_str *cstr, char *str)
 	cstr->str = str;
 
 	/* Parse name token */
-	while (*str != ';' && *str != '=' && !isspace(*str) && *str)
+	while (*str != ';' && *str != '=' && !isspace((unsigned char)*str) && *str)
 		str++;
 
 	/* Bail out if name token is empty */
@@ -83,7 +83,7 @@ parse_cookie_str(struct cookie_str *cstr, char *str)
 
 	for (; *str != ';' && *str; str++) {
 		/* Allow spaces in the value but leave out ending spaces */
-		if (!isspace(*str))
+		if (!isspace((unsigned char)*str))
 			cstr->val_end = str + 1;
 	}
 
diff --git a/src/document/dom/source.c b/src/document/dom/source.c
index 7eba398e..d908ed07 100644
--- a/src/document/dom/source.c
+++ b/src/document/dom/source.c
@@ -259,7 +259,7 @@ render_dom_attribute_source(struct dom_stack *stack, struct dom_node *node, void
 			 * is at the start of the value string. */
 			for (skips = 0; skips < valuelen; skips++) {
 				if ((quoted && skips == 0)
-				    || isspace(value[skips])
+				    || isspace((unsigned char)value[skips])
 				    || (unsigned char)value[skips] < ' ')
 					continue;
 
@@ -276,7 +276,7 @@ render_dom_attribute_source(struct dom_stack *stack, struct dom_node *node, void
 			 * link text. */
 			for (skips = 0; skips < valuelen; skips++) {
 				if ((quoted && skips == 0)
-				    || isspace(value[valuelen - skips - 1])
+				    || isspace((unsigned char)value[valuelen - skips - 1])
 				    || (unsigned char)value[valuelen - skips - 1] < ' ')
 					continue;
 
diff --git a/src/document/html/parser.c b/src/document/html/parser.c
index c581f733..c95fc54a 100644
--- a/src/document/html/parser.c
+++ b/src/document/html/parser.c
@@ -150,7 +150,7 @@ put_chrs(struct html_context *html_context, const char *start, int len)
 
 	case HTML_SPACE_SUPPRESS:
 		html_context->putsp = HTML_SPACE_NORMAL;
-		if (isspace(start[0])) {
+		if (isspace((unsigned char)start[0])) {
 			start++, len--;
 
 			if (!len) {
@@ -162,7 +162,7 @@ put_chrs(struct html_context *html_context, const char *start, int len)
 		break;
 	}
 
-	if (isspace(start[len - 1]) && !html_is_preformatted()) {
+	if (isspace((unsigned char)start[len - 1]) && !html_is_preformatted()) {
 		html_context->putsp = HTML_SPACE_SUPPRESS;
 	}
 	html_context->was_br = 0;
diff --git a/src/document/html/parser/forms.c b/src/document/html/parser/forms.c
index a7a7539e..5dfcc6a3 100644
--- a/src/document/html/parser/forms.c
+++ b/src/document/html/parser/forms.c
@@ -386,8 +386,8 @@ abort:
 		char *q, *s = en;
 		int l = html - en;
 
-		while (l && isspace(s[0])) s++, l--;
-		while (l && isspace(s[l-1])) l--;
+		while (l && isspace((unsigned char)s[0])) s++, l--;
+		while (l && isspace((unsigned char)s[l-1])) l--;
 		q = convert_string(ct, s, l,
 		                   html_context->options->cp,
 		                   CSM_DEFAULT, NULL, NULL, NULL);
@@ -574,8 +574,8 @@ html_option(struct html_context *html_context, char *a,
 		}
 
 se:
-		while (p < html_context->eoff && isspace(*p)) p++;
-		while (p < html_context->eoff && !isspace(*p) && *p != '<') {
+		while (p < html_context->eoff && isspace((unsigned char)*p)) p++;
+		while (p < html_context->eoff && !isspace((unsigned char)*p) && *p != '<') {
 
 sp:
 			add_char_to_string(&str, *p ? *p : ' '), p++;
@@ -584,7 +584,7 @@ sp:
 		r = p;
 		val = str.source; /* Has to be before the possible 'goto end_parse' */
 
-		while (r < html_context->eoff && isspace(*r)) r++;
+		while (r < html_context->eoff && isspace((unsigned char)*r)) r++;
 		if (r >= html_context->eoff) goto end_parse;
 		if (r - 2 <= html_context->eoff && (r[1] == '!' || r[1] == '?')) {
 			p = skip_comment(r, html_context->eoff);
diff --git a/src/document/html/parser/parse.c b/src/document/html/parser/parse.c
index 3e61fef3..70fcc679 100644
--- a/src/document/html/parser/parse.c
+++ b/src/document/html/parser/parse.c
@@ -70,28 +70,28 @@ parse_element(char *e, char *eof,
 
 	while (isident(*e)) next_char();
 
-	if (!isspace(*e) && !end_of_tag(*e) && *e != '/' && *e != ':' && *e != '=')
+	if (!isspace((unsigned char)*e) && !end_of_tag(*e) && *e != '/' && *e != ':' && *e != '=')
 		return -1;
 
 	if (name && namelen) *namelen = e - *name;
 
-	while (isspace(*e) || *e == '/' || *e == ':') next_char();
+	while (isspace((unsigned char)*e) || *e == '/' || *e == ':') next_char();
 
 	/* Skip bad attribute */
-	while (!atchr(*e) && !end_of_tag(*e) && !isspace(*e)) next_char();
+	while (!atchr(*e) && !end_of_tag(*e) && !isspace((unsigned char)*e)) next_char();
 
 	if (attr) *attr = e;
 
 next_attr:
-	while (isspace(*e)) next_char();
+	while (isspace((unsigned char)*e)) next_char();
 
 	/* Skip bad attribute */
-	while (!atchr(*e) && !end_of_tag(*e) && !isspace(*e)) next_char();
+	while (!atchr(*e) && !end_of_tag(*e) && !isspace((unsigned char)*e)) next_char();
 
 	if (end_of_tag(*e)) goto end;
 
 	while (atchr(*e)) next_char();
-	while (isspace(*e)) next_char();
+	while (isspace((unsigned char)*e)) next_char();
 
 	if (*e != '=') {
 		if (end_of_tag(*e)) goto end;
@@ -99,7 +99,7 @@ next_attr:
 	}
 	next_char();
 
-	while (isspace(*e)) next_char();
+	while (isspace((unsigned char)*e)) next_char();
 
 	if (isquote(*e)) {
 		unsigned char quote = *e;
@@ -115,10 +115,10 @@ next_attr:
 		 * long as this is commented out. --pasky */
 		/* if (*e == quote) goto quoted_value; */
 	} else {
-		while (!isspace(*e) && !end_of_tag(*e)) next_char();
+		while (!isspace((unsigned char)*e) && !end_of_tag(*e)) next_char();
 	}
 
-	while (isspace(*e)) next_char();
+	while (isspace((unsigned char)*e)) next_char();
 
 	if (!end_of_tag(*e)) goto next_attr;
 
@@ -169,7 +169,7 @@ next_attr:
 
 	if (found) {
 		if (!isquote(*e)) {
-			while (!isspace(*e) && !end_of_tag(*e)) {
+			while (!isspace((unsigned char)*e) && !end_of_tag(*e)) {
 				if (!*e) goto parse_error;
 				add_chr(attr, attrlen, *e);
 				e++;
@@ -221,7 +221,7 @@ found_endattr:
 
 	} else {
 		if (!isquote(*e)) {
-			while (!isspace(*e) && !end_of_tag(*e)) {
+			while (!isspace((unsigned char)*e) && !end_of_tag(*e)) {
 				if (!*e) goto parse_error;
 				e++;
 			}
@@ -323,14 +323,14 @@ get_width2(char *value, int limited, struct html_context *html_context)
 	for (len = 0; str[len] && str[len] != ','; len++);
 
 	/* Go back, and skip spaces after width if any. */
-	while (len && isspace(str[len - 1])) len--;
+	while (len && isspace((unsigned char)str[len - 1])) len--;
 	if (!len) { return -1; } /* Nothing to parse. */
 
 	/* Is this a percentage ? */
 	if (str[len - 1] == '%') len--, percentage = 1;
 
 	/* Skip spaces between width number and percentage if any. */
-	while (len && isspace(str[len - 1])) len--;
+	while (len && isspace((unsigned char)str[len - 1])) len--;
 	if (!len) { return -1; } /* Nothing to parse. */
 
 	/* Shorten the string a bit, so strtoul() will work on useful
@@ -394,7 +394,7 @@ skip_comment(char *html, char *eof)
 			if (html + 2 <= eof && html[0] == '-' && html[1] == '-') {
 				html += 2;
 				while (html < eof && *html == '-') html++;
-				while (html < eof && isspace(*html)) html++;
+				while (html < eof && isspace((unsigned char)*html)) html++;
 				if (html >= eof) return eof;
 				if (*html == '>') return html + 1;
 				continue;
@@ -693,10 +693,10 @@ main_loop:
 			noupdate = 0;
 		}
 
-		if (isspace(*html) && !html_is_preformatted()) {
+		if (isspace((unsigned char)*html) && !html_is_preformatted()) {
 			char *h = html;
 
-			while (h < eof && isspace(*h))
+			while (h < eof && isspace((unsigned char)*h))
 				h++;
 			if (h + 1 < eof && h[0] == '<' && h[1] == '/') {
 				if (!parse_element(h, eof, &name, &namelen, &attr, &end)) {
@@ -709,9 +709,9 @@ main_loop:
 			html++;
 			if (!(html_context->position + (html - base_pos - 1)))
 				goto skip_w; /* ??? */
-			if (*(html - 1) == ' ') {	/* Do not replace with isspace() ! --Zas */
+			if (*(html - 1) == ' ') {	/* Do not replace with isspace((unsigned char)) ! --Zas */
 				/* BIG performance win; not sure if it doesn't cause any bug */
-				if (html < eof && !isspace(*html)) {
+				if (html < eof && !isspace((unsigned char)*html)) {
 					noupdate = 1;
 					continue;
 				}
@@ -722,7 +722,7 @@ main_loop:
 			}
 
 skip_w:
-			while (html < eof && isspace(*html))
+			while (html < eof && isspace((unsigned char)*html))
 				html++;
 			continue;
 		}
@@ -778,7 +778,7 @@ next_break:
 
 			dotcounter++;
 			base_pos = ++html;
-			if (*html >= ' ' || isspace(*html) || html >= eof) {
+			if (*html >= ' ' || isspace((unsigned char)*html) || html >= eof) {
 				char *dots = (char *)fmem_alloc(dotcounter);
 
 				if (dots) {
@@ -815,7 +815,7 @@ element:
 			while (!parse_element(ee, eof, &nm, NULL, NULL, &ee))
 				if (*nm == '/')
 					goto ng;
-			if (ee < eof && isspace(*ee)) {
+			if (ee < eof && isspace((unsigned char)*ee)) {
 				put_chrs(html_context, " ", 1);
 			}
 		}
diff --git a/src/document/html/renderer.c b/src/document/html/renderer.c
index 7d8c6559..9759766f 100644
--- a/src/document/html/renderer.c
+++ b/src/document/html/renderer.c
@@ -1833,7 +1833,7 @@ html_has_non_space_chars(const char *chars, int charslen)
 	int pos = 0;
 
 	while (pos < charslen)
-		if (!isspace(chars[pos++]))
+		if (!isspace((unsigned char)chars[pos++]))
 			return 1;
 
 	return 0;
diff --git a/src/document/html/tables.c b/src/document/html/tables.c
index 86cc6e76..aed1716f 100644
--- a/src/document/html/tables.c
+++ b/src/document/html/tables.c
@@ -714,10 +714,10 @@ get_table_caption_height(struct html_context *html_context, struct table *table)
 
 	if (!start || !end) return 0;
 
-	while (start < end && isspace(*start))
+	while (start < end && isspace((unsigned char)*start))
 		start++;
 
-	while (start < end && isspace(end[-1]))
+	while (start < end && isspace((unsigned char)end[-1]))
 		end--;
 
 	if (start >= end) return 0;
@@ -1212,10 +1212,10 @@ draw_table_caption(struct html_context *html_context, struct table *table,
 
 	if (!start || !end) return;
 
-	while (start < end && isspace(*start))
+	while (start < end && isspace((unsigned char)*start))
 		start++;
 
-	while (start < end && isspace(end[-1]))
+	while (start < end && isspace((unsigned char)end[-1]))
 		end--;
 
 	if (start >= end) return;
@@ -1252,10 +1252,10 @@ draw_table_bad_html(struct html_context *html_context, struct table *table)
 		char *start = html->start;
 		char *end = html->end;
 
-		while (start < end && isspace(*start))
+		while (start < end && isspace((unsigned char)*start))
 			start++;
 
-		while (start < end && isspace(end[-1]))
+		while (start < end && isspace((unsigned char)end[-1]))
 			end--;
 
 		if (start >= end) continue;
diff --git a/src/document/plain/renderer.c b/src/document/plain/renderer.c
index 84d80d74..72191a44 100644
--- a/src/document/plain/renderer.c
+++ b/src/document/plain/renderer.c
@@ -760,7 +760,7 @@ add_document_lines(struct plain_renderer *renderer)
 				step++;
 			if (step) break;
 
-			if (isspace(source[width])) {
+			if (isspace((unsigned char)source[width])) {
 				last_space = width;
 				if (only_spaces)
 					spaces++;
diff --git a/src/document/xml/renderer2.c b/src/document/xml/renderer2.c
index 221d7aea..82450d53 100644
--- a/src/document/xml/renderer2.c
+++ b/src/document/xml/renderer2.c
@@ -78,10 +78,10 @@ main_loop:
 			noupdate = 0;
 		}
 
-		if (isspace(*html) && !html_is_preformatted()) {
+		if (isspace((unsigned char)*html) && !html_is_preformatted()) {
 			char *h = html;
 
-			while (h < eof && isspace(*h))
+			while (h < eof && isspace((unsigned char)*h))
 				h++;
 			if (h + 1 < eof && h[0] == '<' && h[1] == '/') {
 				if (!parse_element(h, eof, &name, &namelen, &attr, &end)) {
@@ -94,9 +94,9 @@ main_loop:
 			html++;
 			if (!(html_context->position + (html - base_pos - 1)))
 				goto skip_w; /* ??? */
-			if (*(html - 1) == ' ') {	/* Do not replace with isspace() ! --Zas */
+			if (*(html - 1) == ' ') {	/* Do not replace with isspace((unsigned char)) ! --Zas */
 				/* BIG performance win; not sure if it doesn't cause any bug */
-				if (html < eof && !isspace(*html)) {
+				if (html < eof && !isspace((unsigned char)*html)) {
 					noupdate = 1;
 					continue;
 				}
@@ -107,7 +107,7 @@ main_loop:
 			}
 
 skip_w:
-			while (html < eof && isspace(*html))
+			while (html < eof && isspace((unsigned char)*html))
 				html++;
 			continue;
 		}
@@ -163,7 +163,7 @@ next_break:
 
 			dotcounter++;
 			base_pos = ++html;
-			if (*html >= ' ' || isspace(*html) || html >= eof) {
+			if (*html >= ' ' || isspace((unsigned char)*html) || html >= eof) {
 				char *dots = (char *)fmem_alloc(dotcounter);
 
 				if (dots) {
@@ -200,7 +200,7 @@ element:
 ///		while (!parse_element(ee, eof, &nm, NULL, NULL, &ee))
 ///			if (*nm == '/')
 ///					goto ng;
-			if (ee < eof && isspace(*ee)) {
+			if (ee < eof && isspace((unsigned char)*ee)) {
 				put_chrs(html_context, " ", 1);
 			}
 		}
diff --git a/src/dom/configuration.c b/src/dom/configuration.c
index ad4d5709..264716e4 100644
--- a/src/dom/configuration.c
+++ b/src/dom/configuration.c
@@ -28,7 +28,7 @@ normalize_text_node_whitespace(struct dom_node *node)
 		for (j = 0; j < sizeof(buf) && i < node->string.length; i++) {
 			char data = text[i];
 
-			if (isspace(data)) {
+			if (isspace((unsigned char)data)) {
 				if (count == 1)
 					continue;
 
diff --git a/src/dom/select.c b/src/dom/select.c
index 50edf8df..e88f889d 100644
--- a/src/dom/select.c
+++ b/src/dom/select.c
@@ -689,7 +689,7 @@ match_attribute_value(struct dom_select_node *selector, struct dom_node *node)
 				break;
 
 			default:
-				if (isspace(str.string[str.length]))
+				if (isspace((unsigned char)str.string[str.length]))
 					return 1;
 			}
 		}
@@ -704,7 +704,7 @@ match_attribute_value(struct dom_select_node *selector, struct dom_node *node)
 			break;
 
 		default:
-			do_compare = isspace(str.string[0]);
+			do_compare = isspace((unsigned char)str.string[0]);
 		}
 
 		str.length--, str.string++;
diff --git a/src/mime/backend/mailcap.c b/src/mime/backend/mailcap.c
index f6ad5b15..75af4d7a 100644
--- a/src/mime/backend/mailcap.c
+++ b/src/mime/backend/mailcap.c
@@ -247,7 +247,7 @@ get_mailcap_field(char **next)
 	}
 
 	/* Remove trailing whitespace */
-	while (field <= fieldend && isspace(*fieldend))
+	while (field <= fieldend && isspace((unsigned char)*fieldend))
 		*fieldend-- = '\0';
 
 	return field;
diff --git a/src/protocol/http/http_negotiate.c b/src/protocol/http/http_negotiate.c
index 5adaa479..49272108 100644
--- a/src/protocol/http/http_negotiate.c
+++ b/src/protocol/http/http_negotiate.c
@@ -152,7 +152,7 @@ http_negotiate_parse_data(char *data, int type,
 	else
 		data += HTTPNEG_NEG_STRLEN;
 
-	while (*data && isspace((int) *data))
+	while (*data && isspace((unsigned char)(int) *data))
 		data++;
 
 	if (*data == '\0' || *data == ASCII_CR || *data == ASCII_LF)
diff --git a/src/terminal/kbd.c b/src/terminal/kbd.c
index 6fe21760..9431b65a 100644
--- a/src/terminal/kbd.c
+++ b/src/terminal/kbd.c
@@ -801,7 +801,7 @@ get_esc_code(unsigned char *str, int len, char *final_byte,
 
 #ifdef DEBUG_ITRM_QUEUE
 #include <stdio.h>
-#include <ctype.h>	/* isprint() isspace() */
+#include <ctype.h>	/* isprint() isspace((unsigned char)) */
 #endif
 
 int ui_double_esc;
@@ -1144,7 +1144,7 @@ process_queue(struct itrm *itrm)
 		for (i = 0; i < itrm->in.queue.len; i++)
 			if (itrm->in.queue.data[i] == ASCII_ESC)
 				fprintf(stderr, "ESC ");
-			else if (isprint(itrm->in.queue.data[i]) && !isspace(itrm->in.queue.data[i]))
+			else if (isprint(itrm->in.queue.data[i]) && !isspace((unsigned char)itrm->in.queue.data[i]))
 				fprintf(stderr, "%c ", itrm->in.queue.data[i]);
 			else
 				fprintf(stderr, "0x%02x ", itrm->in.queue.data[i]);
diff --git a/src/util/file.c b/src/util/file.c
index 73b22ab2..4d45cd66 100644
--- a/src/util/file.c
+++ b/src/util/file.c
@@ -225,7 +225,7 @@ file_read_line(char *line, size_t *size, FILE *file, int *lineno)
 		 * the line is 'continued'. */
 		(*lineno)++;
 
-		while (line < linepos && isspace(*linepos))
+		while (line < linepos && isspace((unsigned char)*linepos))
 			linepos--;
 
 		if (*linepos != '\\') {
diff --git a/src/util/string.h b/src/util/string.h
index 306db6bc..34940bbe 100644
--- a/src/util/string.h
+++ b/src/util/string.h
@@ -126,10 +126,10 @@ char * c_strcasestr(const char *haystack, const char *needle);
 
 
 #define skip_space(S) \
-	do { while (isspace(*(S))) (S)++; } while (0)
+	do { while (isspace((unsigned char)*(S))) (S)++; } while (0)
 
 #define skip_nonspace(S) \
-	do { while (*(S) && !isspace(*(S))) (S)++; } while (0)
+	do { while (*(S) && !isspace((unsigned char)*(S))) (S)++; } while (0)
 
 #undef isdigit
 #define isdigit(c)	((c) >= '0' && (c) <= '9')
diff --git a/src/viewer/text/form.c b/src/viewer/text/form.c
index f0ef83fd..80962484 100644
--- a/src/viewer/text/form.c
+++ b/src/viewer/text/form.c
@@ -1816,9 +1816,9 @@ field_op(struct session *ses, struct document_view *doc_view,
 			}
 
 			text = &fs->value[fs->state];
-			while (text > fs->value && isspace(*(text - 1)))
+			while (text > fs->value && isspace((unsigned char)*(text - 1)))
 				--text;
-			while (text > fs->value && !isspace(*(text - 1)))
+			while (text > fs->value && !isspace((unsigned char)*(text - 1)))
 				--text;
 			if (*text == ASCII_LF
 			    && text != &fs->value[fs->state - 1])
@@ -1832,20 +1832,20 @@ field_op(struct session *ses, struct document_view *doc_view,
 
 		case ACT_EDIT_MOVE_BACKWARD_WORD:
 			while (fs->state > 0
-			       && isspace(fs->value[fs->state - 1]))
+			       && isspace((unsigned char)fs->value[fs->state - 1]))
 				--fs->state;
 			while (fs->state > 0
-			       && !isspace(fs->value[fs->state - 1]))
+			       && !isspace((unsigned char)fs->value[fs->state - 1]))
 				--fs->state;
 			break;
 
 		case ACT_EDIT_MOVE_FORWARD_WORD:
-			while (isspace(fs->value[fs->state]))
+			while (isspace((unsigned char)fs->value[fs->state]))
 				++fs->state;
 			while (fs->value[fs->state]
-			       && !isspace(fs->value[fs->state]))
+			       && !isspace((unsigned char)fs->value[fs->state]))
 				++fs->state;
-			while (isspace(fs->value[fs->state]))
+			while (isspace((unsigned char)fs->value[fs->state]))
 				++fs->state;
 			break;