diff --git a/Include/pyerrors.h b/Include/pyerrors.h
index 8747aec..c8c3d82 100644
--- a/Include/pyerrors.h
+++ b/Include/pyerrors.h
@@ -60,6 +60,13 @@
 
 extern DL_IMPORT(PyObject *) PyExc_MemoryErrorInst;
 
+/* Predefined warning categories */
+extern DL_IMPORT(PyObject *) PyExc_Warning;
+extern DL_IMPORT(PyObject *) PyExc_UserWarning;
+extern DL_IMPORT(PyObject *) PyExc_DeprecationWarning;
+extern DL_IMPORT(PyObject *) PyExc_SyntaxWarning;
+extern DL_IMPORT(PyObject *) PyExc_RuntimeWarning;
+
 
 /* Convenience functions */
 
@@ -85,6 +92,9 @@
                                          PyObject *dict);
 extern DL_IMPORT(void) PyErr_WriteUnraisable(PyObject *);
 
+/* Issue a warning or exception */
+extern DL_IMPORT(int) PyErr_Warn(PyObject *, char *);
+
 /* In sigcheck.c or signalmodule.c */
 extern DL_IMPORT(int) PyErr_CheckSignals(void);
 extern DL_IMPORT(void) PyErr_SetInterrupt(void);