diff --git a/cfg/gtk.cfg b/cfg/gtk.cfg
index 391ba6619..2d793484c 100644
--- a/cfg/gtk.cfg
+++ b/cfg/gtk.cfg
@@ -2375,9 +2375,20 @@
     <leak-ignore/>
     <noreturn>false</noreturn>
   </function>
+  <!-- gint g_fprintf (FILE *file, gchar const *format, ...); -->
   <function name="g_fprintf">
     <leak-ignore/>
     <noreturn>false</noreturn>
+    <returnValue type="gint"/>
+    <arg nr="1">
+      <not-null/>
+      <not-uninit/>
+    </arg>
+    <formatstr/>
+    <arg nr="2" direction="in">
+      <not-uninit/>
+      <formatstr/>
+    </arg>
   </function>
   <function name="g_get_application_name">
     <leak-ignore/>
@@ -3024,9 +3035,16 @@
       <strz/>
     </arg>
   </function>
+  <!-- gint g_printf (gchar const *format, ...); -->
   <function name="g_printf">
     <leak-ignore/>
     <noreturn>false</noreturn>
+    <returnValue type="gint"/>
+    <formatstr/>
+    <arg nr="1" direction="in">
+      <not-uninit/>
+      <formatstr/>
+    </arg>
   </function>
   <function name="g_printf_string_upper_bound">
     <leak-ignore/>
@@ -3307,17 +3325,40 @@
     <leak-ignore/>
     <noreturn>false</noreturn>
   </function>
+  <!-- gint g_sprintf (gchar *string, gchar const *format, ...); -->
   <function name="g_sprintf">
     <leak-ignore/>
     <noreturn>false</noreturn>
+    <returnValue type="gint"/>
+    <arg nr="1" direction="out">
+      <not-null/>
+    </arg>
+    <formatstr/>
+    <arg nr="2" direction="in">
+      <not-null/>
+      <not-uninit/>
+      <strz/>
+      <formatstr/>
+    </arg>
   </function>
   <function name="g_stpcpy">
     <leak-ignore/>
     <noreturn>false</noreturn>
   </function>
+  <!-- gboolean g_str_equal (gconstpointer v1, gconstpointer v2); -->
   <function name="g_str_equal">
     <leak-ignore/>
     <noreturn>false</noreturn>
+    <returnValue type="gboolean"/>
+    <use-retval/>
+    <arg nr="1" direction="in">
+      <not-null/>
+      <not-uninit/>
+    </arg>
+    <arg nr="2" direction="in">
+      <not-null/>
+      <not-uninit/>
+    </arg>
   </function>
   <function name="g_str_has_prefix">
     <leak-ignore/>
@@ -3402,21 +3443,57 @@
     <leak-ignore/>
     <noreturn>false</noreturn>
   </function>
+  <!-- const gchar * g_strerror (gint errnum); -->
   <function name="g_strerror">
     <leak-ignore/>
     <noreturn>false</noreturn>
+    <returnValue type="const gchar *"/>
+    <arg nr="1" direction="in">
+      <not-uninit/>
+    </arg>
   </function>
   <function name="g_strip_context">
     <leak-ignore/>
     <noreturn>false</noreturn>
   </function>
+  <!-- gsize g_strlcat (gchar *dest, const gchar *src, gsize dest_size); -->
   <function name="g_strlcat">
     <leak-ignore/>
     <noreturn>false</noreturn>
+    <returnValue type="gsize"/>
+    <arg nr="1" direction="inout">
+      <not-null/>
+      <not-uninit/>
+      <minsize type="argvalue" arg="3"/>
+    </arg>
+    <arg nr="2" direction="in">
+      <not-null/>
+      <not-uninit/>
+      <strz/>
+    </arg>
+    <arg nr="3" direction="in">
+      <not-uninit/>
+      <not-bool/>
+    </arg>
   </function>
+  <!-- gsize g_strlcpy (gchar *dest, const gchar *src, gsize dest_size); -->
   <function name="g_strlcpy">
     <leak-ignore/>
     <noreturn>false</noreturn>
+    <returnValue type="gsize"/>
+    <arg nr="1" direction="out">
+      <not-null/>
+      <minsize type="argvalue" arg="3"/>
+    </arg>
+    <arg nr="2" direction="in">
+      <not-null/>
+      <not-uninit/>
+      <strz/>
+    </arg>
+    <arg nr="3" direction="in">
+      <not-uninit/>
+      <not-bool/>
+    </arg>
   </function>
   <!-- gint g_strncasecmp (const gchar *s1, const gchar *s2, guint n); -->
   <function name="g_strncasecmp">
@@ -7465,9 +7542,15 @@
     <leak-ignore/>
     <noreturn>false</noreturn>
   </function>
+  <!-- void gtk_exit (gint error_code); -->
   <function name="gtk_exit">
-    <leak-ignore/>
-    <noreturn>false</noreturn>
+    <noreturn>true</noreturn>
+    <returnValue type="void"/>
+    <warn severity="style" alternatives="exit" reason="Obsolete">gtk_exit is deprecated and should not be used in newly-written code. Use the standard exit() function instead.</warn>
+    <arg nr="1" direction="in">
+      <not-uninit/>
+      <not-bool/>
+    </arg>
   </function>
   <function name="gtk_false">
     <leak-ignore/>