diff -r c0cc31c5781c Objects/cobject.c
--- a/Objects/cobject.c	Tue May 05 15:42:49 2009 -0700
+++ b/Objects/cobject.c	Tue May 05 16:43:56 2009 -0700
@@ -9,11 +9,30 @@
 typedef void (*destructor1)(void *);
 typedef void (*destructor2)(void *, void*);
 
+
+static int deprecation_exception(void)
+{
+    static int issued_warning = 0;
+    if (!issued_warning) {
+        issued_warning = 1;
+        if (PyErr_WarnEx(PyExc_DeprecationWarning,
+                 "The CObject API is deprecated as of Python 3.1.  "
+                 "Please convert to using the Capsule API.", 1) != 0) {
+            return 1;
+        }
+    }
+    return 0;
+}
+
 PyObject *
 PyCObject_FromVoidPtr(void *cobj, void (*destr)(void *))
 {
     PyCObject *self;
 
+    if (deprecation_exception()) {
+        return NULL;
+    }
+
     self = PyObject_NEW(PyCObject, &PyCObject_Type);
     if (self == NULL)
         return NULL;
@@ -30,6 +49,10 @@
 {
     PyCObject *self;
 
+    if (deprecation_exception()) {
+        return NULL;
+    }
+
     if (!desc) {
         PyErr_SetString(PyExc_TypeError,
                         "PyCObject_FromVoidPtrAndDesc called with null"