diff --git a/src/xml.c b/src/xml.c
index 861b919..640c47d 100644
--- a/src/xml.c
+++ b/src/xml.c
@@ -19,8 +19,8 @@ static struct ctx {
 	char *filename;
 	xmlDoc *doc;
 	xmlXPathContextPtr xpath_ctx_ptr;
-	char *nodename;
-	char *value;
+	const char *nodename;
+	const char *value;
 	xmlNode *node;
 	enum {
 		XML_MODE_SETTING = 0,
@@ -196,7 +196,7 @@ xml_finish(void)
 }
 
 void
-xml_set(char *nodename, char *value)
+xml_set(const char *nodename, const char *value)
 {
 	ctx.nodename = nodename;
 	ctx.value = value;
@@ -205,7 +205,7 @@ xml_set(char *nodename, char *value)
 }
 
 void
-xml_set_num(char *nodename, double value)
+xml_set_num(const char *nodename, double value)
 {
 	char buf[64];
 	snprintf(buf, sizeof(buf), "%.0f", value);
@@ -215,8 +215,8 @@ xml_set_num(char *nodename, double value)
 	xml_tree_walk(xmlDocGetRootElement(ctx.doc));
 }
 
-char *
-xml_get(char *nodename)
+const char *
+xml_get(const char *nodename)
 {
 	ctx.nodename = nodename;
 	ctx.mode = XML_MODE_GETTING;
@@ -225,7 +225,7 @@ xml_get(char *nodename)
 }
 
 int
-xml_get_int(char *nodename)
+xml_get_int(const char *nodename)
 {
 	ctx.nodename = nodename;
 	ctx.mode = XML_MODE_GETTING;
@@ -234,9 +234,9 @@ xml_get_int(char *nodename)
 }
 
 int
-xml_get_bool_text(char *nodename)
+xml_get_bool_text(const char *nodename)
 {
-	char *value = xml_get(nodename);
+	const char *value = xml_get(nodename);
 
 	/* handle <foo></foo> and <foo /> where no value has been specified */
 	if (!value || !*value) {
@@ -263,7 +263,7 @@ xml_get_node(char *nodename)
 }
 
 char *
-xpath_get_content(char *xpath_expr)
+xpath_get_content(const char *xpath_expr)
 {
 	xmlChar *ret = NULL;
 	xmlXPathObjectPtr object = xmlXPathEvalExpression((xmlChar *)xpath_expr, ctx.xpath_ctx_ptr);
diff --git a/src/xml.h b/src/xml.h
index 851e24b..ff40501 100644
--- a/src/xml.h
+++ b/src/xml.h
@@ -7,17 +7,17 @@ void xml_init(const char *filename);
 void xml_save(void);
 void xml_save_as(const char *filename);
 void xml_finish(void);
-void xml_set(char *nodename, char *value);
-void xml_set_num(char *nodename, double value);
-char *xml_get(char *nodename);
-int xml_get_int(char *nodename);
-int xml_get_bool_text(char *nodename);
+void xml_set(const char *nodename, const char *value);
+void xml_set_num(const char *nodename, double value);
+const char *xml_get(const char *nodename);
+int xml_get_int(const char *nodename);
+int xml_get_bool_text(const char *nodename);
 
 /**
  * xpath_get_content() - Get content of node specified by xpath
  * @xpath_expr: xpath expression for node
  */
-char *xpath_get_content(char *xpath_expr);
+char *xpath_get_content(const char *xpath_expr);
 
 /**
  * xpath_add_node - add xml nodes from xpath
diff --git a/tweaks-qt/maindialog.cpp b/tweaks-qt/maindialog.cpp
index b9e7690..af0d090 100644
--- a/tweaks-qt/maindialog.cpp
+++ b/tweaks-qt/maindialog.cpp
@@ -53,7 +53,7 @@ void MainDialog::activate()
     struct themes openbox_themes = { 0 };
     theme_find(&openbox_themes, "themes", "openbox-3/themerc");
     int active = -1;
-    char *active_id = xml_get((char *)"/labwc_config/theme/name");
+    char *active_id = xml_get("/labwc_config/theme/name");
     for (int i = 0; i < openbox_themes.nr; ++i) {
         struct theme *theme = openbox_themes.data + i;
         if (active_id && !strcmp(theme->name, active_id)) {
@@ -67,7 +67,7 @@ void MainDialog::activate()
     theme_free_vector(&openbox_themes);
 
     /* Corner Radius */
-    ui->cornerRadius->setValue(xml_get_int((char *)"/labwc_config/theme/cornerradius"));
+    ui->cornerRadius->setValue(xml_get_int("/labwc_config/theme/cornerradius"));
 
     /* # MOUSE & TOUCHPAD */
 
@@ -96,13 +96,13 @@ void MainDialog::activate()
     ui->naturalScroll->addItem("no");
     ui->naturalScroll->addItem("yes");
     ui->naturalScroll->setCurrentIndex(
-            xml_get_bool_text((char *)"/labwc_config/libinput/device/naturalscroll"));
+            xml_get_bool_text("/labwc_config/libinput/device/naturalscroll"));
 
     /* # LANGUAGE */
 
     /* Keyboard Layout */
     GList *keyboard_layouts = NULL;
-    keyboard_layouts_init(&keyboard_layouts, (char *)"/usr/share/X11/xkb/rules/evdev.lst");
+    keyboard_layouts_init(&keyboard_layouts, "/usr/share/X11/xkb/rules/evdev.lst");
     char xkb_default_layout[1024];
     environment_get(xkb_default_layout, sizeof(xkb_default_layout), "XKB_DEFAULT_LAYOUT");
     active = -1;
@@ -128,9 +128,9 @@ void MainDialog::activate()
 void MainDialog::onApply()
 {
     /* ~/.config/labwc/rc.xml */
-    xml_set_num((char *)"/labwc_config/theme/cornerradius", ui->cornerRadius->value());
-    xml_set((char *)"/labwc_config/theme/name", ui->openboxTheme->currentText().toLatin1().data());
-    xml_set((char *)"/labwc_config/libinput/device/naturalscroll",
+    xml_set_num("/labwc_config/theme/cornerradius", ui->cornerRadius->value());
+    xml_set("/labwc_config/theme/name", ui->openboxTheme->currentText().toLatin1().data());
+    xml_set("/labwc_config/libinput/device/naturalscroll",
             ui->naturalScroll->currentText().toLatin1().data());
     xml_save();