diff --git a/cfg/gtk.cfg b/cfg/gtk.cfg
index aafd680c5..53e545dd9 100644
--- a/cfg/gtk.cfg
+++ b/cfg/gtk.cfg
@@ -3238,13 +3238,51 @@
     <leak-ignore/>
     <noreturn>false</noreturn>
   </function>
+  <!-- void g_set_error (GError **err,
+                         GQuark domain,
+                         gint code,
+                         const gchar *format,
+                         ...); -->
   <function name="g_set_error">
     <leak-ignore/>
     <noreturn>false</noreturn>
+    <returnValue type="void"/>
+    <arg nr="1" direction="out">
+      <not-uninit/>
+    </arg>
+    <arg nr="2">
+      <not-uninit/>
+    </arg>
+    <arg nr="3" direction="in">
+      <not-uninit/>
+    </arg>
+    <formatstr/>
+    <arg nr="4" direction="in">
+      <not-uninit/>
+      <formatstr/>
+    </arg>
   </function>
+  <!-- void g_set_error_literal (GError **err,
+                                 GQuark domain,
+                                 gint code,
+                                 const gchar *message); -->
   <function name="g_set_error_literal">
     <leak-ignore/>
     <noreturn>false</noreturn>
+    <returnValue type="void"/>
+    <arg nr="1" direction="out">
+      <not-uninit/>
+    </arg>
+    <arg nr="2">
+      <not-uninit/>
+    </arg>
+    <arg nr="3" direction="in">
+      <not-uninit/>
+    </arg>
+    <arg nr="4" direction="in">
+      <not-uninit/>
+      <strz/>
+    </arg>
   </function>
   <function name="g_set_prgname">
     <leak-ignore/>