Index: readline.c
===================================================================
--- readline.c	(revision 5666)
+++ readline.c	(working copy)
@@ -169,7 +169,7 @@
 
     /* find first word (backwards) */
     while (start > 0) {
-        if (!isspace(term_cmd_buf[start])) {
+        if (!CTYPE(isspace, term_cmd_buf[start])) {
             break;
         }
 
@@ -178,7 +178,7 @@
 
     /* find first space (backwards) */
     while (start > 0) {
-        if (isspace(term_cmd_buf[start])) {
+        if (CTYPE(isspace, term_cmd_buf[start])) {
             ++start;
             break;
         }
Index: block-vvfat.c
===================================================================
--- block-vvfat.c	(revision 5666)
+++ block-vvfat.c	(working copy)
@@ -1056,7 +1056,7 @@
 
     i = strrchr(dirname, ':') - dirname;
     assert(i >= 3);
-    if (dirname[i-2] == ':' && isalpha(dirname[i-1]))
+    if (dirname[i-2] == ':' && CTYPE(isalpha, dirname[i-1]))
 	/* workaround for DOS drive names */
 	dirname += i-1;
     else
Index: target-ppc/translate_init.c
===================================================================
--- target-ppc/translate_init.c	(revision 5666)
+++ target-ppc/translate_init.c	(working copy)
@@ -9458,7 +9458,7 @@
         p = name;
     check_pvr:
         for (i = 0; i < 8; i++) {
-            if (!isxdigit(*p++))
+            if (!CTYPE(isxdigit, *p++))
                 break;
         }
         if (i == 8)
Index: net.c
===================================================================
--- net.c	(revision 5666)
+++ net.c	(working copy)
@@ -279,7 +279,7 @@
     if (buf[0] == '\0') {
         saddr->sin_addr.s_addr = 0;
     } else {
-        if (isdigit(buf[0])) {
+        if (CTYPE(isdigit, buf[0])) {
             if (!inet_aton(buf, &saddr->sin_addr))
                 return -1;
         } else {
Index: cutils.c
===================================================================
--- cutils.c	(revision 5666)
+++ cutils.c	(working copy)
@@ -72,7 +72,7 @@
     p = str;
     q = val;
     while (*q != '\0') {
-        if (toupper(*p) != toupper(*q))
+        if (CTYPE(toupper, *p) != CTYPE(toupper, *q))
             return 0;
         p++;
         q++;
Index: audio/audio.c
===================================================================
--- audio/audio.c	(revision 5666)
+++ audio/audio.c	(working copy)
@@ -215,7 +215,7 @@
         pstrcat (r, len + sizeof (qemu_prefix), s);
 
         for (i = 0; i < len; ++i) {
-            u[i] = toupper (u[i]);
+            u[i] = CTYPE(toupper, u[i]);
         }
     }
     return r;
@@ -470,7 +470,7 @@
 
         /* copy while upper-casing, including trailing zero */
         for (i = 0; i <= preflen; ++i) {
-            optname[i + sizeof (qemu_prefix) - 1] = toupper (prefix[i]);
+            optname[i + sizeof (qemu_prefix) - 1] = CTYPE(toupper, prefix[i]);
         }
         pstrcat (optname, optlen, "_");
         pstrcat (optname, optlen, opt->name);
Index: qemu-common.h
===================================================================
--- qemu-common.h	(revision 5666)
+++ qemu-common.h	(working copy)
@@ -93,6 +93,17 @@
 int stristart(const char *str, const char *val, const char **ptr);
 time_t mktimegm(struct tm *tm);
 
+#define CTYPE(isfoobar,argumentchar) (isfoobar((unsigned char)(argumentchar)))
+  /* One must not pass a plain `char' to isupper, toupper, et al.  If
+   * it has the top bit set (ie, is negative if your chars are
+   * signed), undefined behaviour results.  The <ctype.h> functions
+   * are defined to take the value of an unsigned char, as an int.
+   * So use this macro.  You may pass toupper et al for isfoobar.
+   * Do not pass EOF as a character to this macro.  If you might have
+   * EOF then you ought to have it in an int representing an unsigned
+   * char, which is safe for the ctype macros directly.  Or test separately.
+   * Obviously don't use this for floating point things like isnan! */
+
 void *qemu_malloc(size_t size);
 void *qemu_realloc(void *ptr, size_t size);
 void *qemu_mallocz(size_t size);
Index: monitor.c
===================================================================
--- monitor.c	(revision 5666)
+++ monitor.c	(working copy)
@@ -1933,7 +1933,7 @@
 {
     if (pch != '\0') {
         pch++;
-        while (isspace(*pch))
+        while (CTYPE(isspace, *pch))
             pch++;
     }
 }
@@ -1992,7 +1992,7 @@
                     *q++ = *pch;
                 pch++;
             }
-            while (isspace(*pch))
+            while (CTYPE(isspace, *pch))
                 pch++;
             *q = 0;
             ret = get_monitor_def(&reg, buf);
@@ -2017,7 +2017,7 @@
             expr_error("invalid char in expression");
         }
         pch = p;
-        while (isspace(*pch))
+        while (CTYPE(isspace, *pch))
             pch++;
         break;
     }
@@ -2111,7 +2111,7 @@
         *pp = pch;
         return -1;
     }
-    while (isspace(*pch))
+    while (CTYPE(isspace, *pch))
         pch++;
     *pval = expr_sum();
     *pp = pch;
@@ -2126,7 +2126,7 @@
 
     q = buf;
     p = *pp;
-    while (isspace(*p))
+    while (CTYPE(isspace, *p))
         p++;
     if (*p == '\0') {
     fail:
@@ -2171,7 +2171,7 @@
         }
         p++;
     } else {
-        while (*p != '\0' && !isspace(*p)) {
+        while (*p != '\0' && !CTYPE(isspace, *p)) {
             if ((q - buf) < buf_size - 1) {
                 *q++ = *p;
             }
@@ -2217,12 +2217,12 @@
     /* extract the command name */
     p = cmdline;
     q = cmdname;
-    while (isspace(*p))
+    while (CTYPE(isspace, *p))
         p++;
     if (*p == '\0')
         return;
     pstart = p;
-    while (*p != '\0' && *p != '/' && !isspace(*p))
+    while (*p != '\0' && *p != '/' && !CTYPE(isspace, *p))
         p++;
     len = p - pstart;
     if (len > sizeof(cmdname) - 1)
@@ -2258,7 +2258,7 @@
                 int ret;
                 char *str;
 
-                while (isspace(*p))
+                while (CTYPE(isspace, *p))
                     p++;
                 if (*typestr == '?') {
                     typestr++;
@@ -2299,15 +2299,15 @@
             {
                 int count, format, size;
 
-                while (isspace(*p))
+                while (CTYPE(isspace, *p))
                     p++;
                 if (*p == '/') {
                     /* format found */
                     p++;
                     count = 1;
-                    if (isdigit(*p)) {
+                    if (CTYPE(isdigit, *p)) {
                         count = 0;
-                        while (isdigit(*p)) {
+                        while (CTYPE(isdigit, *p)) {
                             count = count * 10 + (*p - '0');
                             p++;
                         }
@@ -2346,7 +2346,7 @@
                         }
                     }
                 next:
-                    if (*p != '\0' && !isspace(*p)) {
+                    if (*p != '\0' && !CTYPE(isspace, *p)) {
                         term_printf("invalid char in format: '%c'\n", *p);
                         goto fail;
                     }
@@ -2380,7 +2380,7 @@
             {
                 int64_t val;
 
-                while (isspace(*p))
+                while (CTYPE(isspace, *p))
                     p++;
                 if (*typestr == '?' || *typestr == '.') {
                     if (*typestr == '?') {
@@ -2391,7 +2391,7 @@
                     } else {
                         if (*p == '.') {
                             p++;
-                            while (isspace(*p))
+                            while (CTYPE(isspace, *p))
                                 p++;
                             has_arg = 1;
                         } else {
@@ -2436,7 +2436,7 @@
                 c = *typestr++;
                 if (c == '\0')
                     goto bad_type;
-                while (isspace(*p))
+                while (CTYPE(isspace, *p))
                     p++;
                 has_option = 0;
                 if (*p == '-') {
@@ -2461,7 +2461,7 @@
         }
     }
     /* check that all arguments were parsed */
-    while (isspace(*p))
+    while (CTYPE(isspace, *p))
         p++;
     if (*p != '\0') {
         term_printf("%s: extraneous characters at the end of line\n",
@@ -2609,7 +2609,7 @@
     p = cmdline;
     nb_args = 0;
     for(;;) {
-        while (isspace(*p))
+        while (CTYPE(isspace, *p))
             p++;
         if (*p == '\0')
             break;
@@ -2643,7 +2643,7 @@
     /* if the line ends with a space, it means we want to complete the
        next arg */
     len = strlen(cmdline);
-    if (len > 0 && isspace(cmdline[len - 1])) {
+    if (len > 0 && CTYPE(isspace, cmdline[len - 1])) {
         if (nb_args >= MAX_ARGS)
             return;
         args[nb_args++] = qemu_strdup("");