diff --git a/src/interface/interface_backend_udev.c b/src/interface/interface_backend_udev.c
index b7b06ed67a..29d91d3539 100644
--- a/src/interface/interface_backend_udev.c
+++ b/src/interface/interface_backend_udev.c
@@ -567,7 +567,7 @@ udevBridgeScanDirFilter(const struct dirent *entry)
      */
     if (strlen(entry->d_name) >= 5) {
         if (STRPREFIX(entry->d_name, VIR_NET_GENERATED_TAP_PREFIX) &&
-            c_isdigit(entry->d_name[4]))
+            g_ascii_isdigit(entry->d_name[4]))
             return 0;
     }
 
diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
index 132e04b147..1be2a789d5 100644
--- a/src/libxl/libxl_conf.c
+++ b/src/libxl/libxl_conf.c
@@ -29,7 +29,6 @@
 #include "internal.h"
 #include "virlog.h"
 #include "virerror.h"
-#include "c-ctype.h"
 #include "datatypes.h"
 #include "virconf.h"
 #include "virfile.h"
@@ -1860,7 +1859,7 @@ libxlDriverGetDom0MaxmemConf(libxlDriverConfigPtr cfg,
                 char *p = mem_tokens[j] + 4;
                 unsigned long long multiplier = 1;
 
-                while (c_isdigit(*p))
+                while (g_ascii_isdigit(*p))
                     p++;
                 if (virStrToLong_ull(mem_tokens[j] + 4, &p, 10, maxmem) < 0)
                     break;
diff --git a/src/storage/parthelper.c b/src/storage/parthelper.c
index f1a8cc01ea..761a7f93fc 100644
--- a/src/storage/parthelper.c
+++ b/src/storage/parthelper.c
@@ -38,7 +38,6 @@
 
 #include "virutil.h"
 #include "virfile.h"
-#include "c-ctype.h"
 #include "virstring.h"
 #include "virgettext.h"
 
@@ -87,7 +86,7 @@ int main(int argc, char **argv)
          * path, then append the "p" partition separator. Otherwise, if
          * the path ends with a letter already, then no need for a separator.
          */
-        if (c_isdigit(path[strlen(path)-1]) || devmap_partsep)
+        if (g_ascii_isdigit(path[strlen(path)-1]) || devmap_partsep)
             partsep = "p";
         else
             partsep = "";
@@ -97,7 +96,7 @@ int main(int argc, char **argv)
             return 2;
 
         partsep = *canonical_path &&
-            c_isdigit(canonical_path[strlen(canonical_path)-1]) ? "p" : "";
+            g_ascii_isdigit(canonical_path[strlen(canonical_path)-1]) ? "p" : "";
     }
 
     if ((dev = ped_device_get(path)) == NULL) {
diff --git a/src/util/virbitmap.c b/src/util/virbitmap.c
index 9bdb785025..15addee2e9 100644
--- a/src/util/virbitmap.c
+++ b/src/util/virbitmap.c
@@ -26,7 +26,6 @@
 #include "virbitmap.h"
 #include "viralloc.h"
 #include "virbuffer.h"
-#include "c-ctype.h"
 #include "virstring.h"
 #include "virutil.h"
 #include "virerror.h"
@@ -506,7 +505,7 @@ virBitmapParseSeparator(const char *str,
             neg = true;
         }
 
-        if (!c_isdigit(*cur))
+        if (!g_ascii_isdigit(*cur))
             goto error;
 
         if (virStrToLong_i(cur, &tmp, 10, &start) < 0)
@@ -642,7 +641,7 @@ virBitmapParseUnlimited(const char *str)
             neg = true;
         }
 
-        if (!c_isdigit(*cur))
+        if (!g_ascii_isdigit(*cur))
             goto error;
 
         if (virStrToLong_i(cur, &tmp, 10, &start) < 0)
diff --git a/src/util/virconf.c b/src/util/virconf.c
index a9a7148701..3b45436499 100644
--- a/src/util/virconf.c
+++ b/src/util/virconf.c
@@ -29,7 +29,6 @@
 #include "virbuffer.h"
 #include "virconf.h"
 #include "virutil.h"
-#include "c-ctype.h"
 #include "virlog.h"
 #include "viralloc.h"
 #include "virfile.h"
@@ -350,11 +349,11 @@ virConfParseLong(virConfParserCtxtPtr ctxt, long long *val)
     } else if (CUR == '+') {
         NEXT;
     }
-    if ((ctxt->cur >= ctxt->end) || (!c_isdigit(CUR))) {
+    if ((ctxt->cur >= ctxt->end) || (!g_ascii_isdigit(CUR))) {
         virConfError(ctxt, VIR_ERR_CONF_SYNTAX, _("unterminated number"));
         return -1;
     }
-    while ((ctxt->cur < ctxt->end) && (c_isdigit(CUR))) {
+    while ((ctxt->cur < ctxt->end) && (g_ascii_isdigit(CUR))) {
         l = l * 10 + (CUR - '0');
         NEXT;
     }
@@ -514,7 +513,7 @@ virConfParseValue(virConfParserCtxtPtr ctxt)
             virConfFreeList(lst);
             return NULL;
         }
-    } else if (c_isdigit(CUR) || (CUR == '-') || (CUR == '+')) {
+    } else if (g_ascii_isdigit(CUR) || (CUR == '-') || (CUR == '+')) {
         if (ctxt->conf->flags & VIR_CONF_FLAG_VMX_FORMAT) {
             virConfError(ctxt, VIR_ERR_CONF_SYNTAX,
                          _("numbers not allowed in VMX format"));
diff --git a/src/util/virfile.c b/src/util/virfile.c
index 0eea66eb27..4fd865dd83 100644
--- a/src/util/virfile.c
+++ b/src/util/virfile.c
@@ -80,8 +80,6 @@
 #include "virstring.h"
 #include "virutil.h"
 
-#include "c-ctype.h"
-
 #define VIR_FROM_THIS VIR_FROM_NONE
 
 VIR_LOG_INIT("util.file");
@@ -696,7 +694,7 @@ static int virFileLoopDeviceOpenSearch(char **dev_name)
          * new kernels have a dev named 'loop-control'
          */
         if (!STRPREFIX(de->d_name, "loop") ||
-            !c_isdigit(de->d_name[4]))
+            !g_ascii_isdigit(de->d_name[4]))
             continue;
 
         looppath = g_strdup_printf("/dev/%s", de->d_name);