diff --git a/cfg/ruby.cfg b/cfg/ruby.cfg
index 1b54eeef4..fbf037fb1 100644
--- a/cfg/ruby.cfg
+++ b/cfg/ruby.cfg
@@ -1,6 +1,78 @@
 <?xml version="1.0"?>
 <def format="2">
   <!-- Ruby C API. see https://docs.ruby-lang.org/en/2.5.0/extension_rdoc.html -->
+  <!-- INT2NUM() is a macro resulting in something like this: VALUE INT2NUM(int v) -->
+  <!-- UINT2NUM() is something like this: VALUE UINT2NUM(unsigned int v) -->
+  <!-- LONG2NUM() is something like this: VALUE LONG2NUM(long v) -->
+  <!-- ULONG2NUM() is something like this: VALUE ULONG2NUM(unsigned long v) -->
+  <!-- LL2NUM() is something like this: VALUE LL2NUM(long long v) -->
+  <!-- ULL2NUM() is something like this: VALUE ULL2NUM(unsigned long long v) -->
+  <function name="INT2NUM,UINT2NUM,LONG2NUM,ULONG2NUM,LL2NUM,ULL2NUM">
+    <noreturn>false</noreturn>
+    <returnValue type="VALUE"/>
+    <use-retval/>
+    <arg nr="1" direction="in">
+      <not-uninit/>
+    </arg>
+  </function>
+  <!-- NUM2INT() is something like this: int NUM2INT(VALUE v) -->
+  <!-- FIX2INT() is something like this: int FIX2INT(VALUE v) -->
+  <function name="NUM2INT,FIX2INT">
+    <noreturn>false</noreturn>
+    <returnValue type="int"/>
+    <use-retval/>
+    <arg nr="1" direction="in">
+      <not-uninit/>
+    </arg>
+  </function>
+  <!-- NUM2UINT() is something like this: unsigned int NUM2UINT(VALUE v) -->
+  <!-- FIX2UINT() is something like this: unsigned int FIX2UINT(VALUE v) -->
+  <function name="NUM2UINT,FIX2UINT">
+    <noreturn>false</noreturn>
+    <returnValue type="unsigned int"/>
+    <use-retval/>
+    <arg nr="1" direction="in">
+      <not-uninit/>
+    </arg>
+  </function>
+  <!-- NUM2LONG() is something like this: long NUM2LONG(VALUE v) -->
+  <!-- FIX2LONG() is something like this: long FIX2LONG(VALUE v) -->
+  <function name="NUM2LONG,FIX2LONG">
+    <noreturn>false</noreturn>
+    <returnValue type="long"/>
+    <use-retval/>
+    <arg nr="1" direction="in">
+      <not-uninit/>
+    </arg>
+  </function>
+  <!-- NUM2ULONG() is something like this: unsigned long NUM2ULONG(VALUE v) -->
+  <!-- FIX2ULONG() is something like this: unsigned long FIX2ULONG(VALUE v) -->
+  <function name="NUM2ULONG,FIX2ULONG">
+    <noreturn>false</noreturn>
+    <returnValue type="unsigned long"/>
+    <use-retval/>
+    <arg nr="1" direction="in">
+      <not-uninit/>
+    </arg>
+  </function>
+  <!-- NUM2LL() is something like this: long long NUM2LL(VALUE v) -->
+  <function name="NUM2LL">
+    <noreturn>false</noreturn>
+    <returnValue type="long long"/>
+    <use-retval/>
+    <arg nr="1" direction="in">
+      <not-uninit/>
+    </arg>
+  </function>
+  <!-- NUM2ULL()  is something like this: unsigned long long NUM2ULL(VALUE v) -->
+  <function name="NUM2ULL">
+    <noreturn>false</noreturn>
+    <returnValue type="unsigned long long"/>
+    <use-retval/>
+    <arg nr="1" direction="in">
+      <not-uninit/>
+    </arg>
+  </function>
   <!-- void rb_define_const(VALUE klass, const char *name, VALUE val)  -->
   <function name="rb_define_const">
     <leak-ignore/>
@@ -66,4 +138,5 @@
     </arg>
   </function>
   <podtype name="ID"/>
+  <podtype name="VALUE" sign="u"/>
 </def>