diff --git a/Include/fileobject.h b/Include/fileobject.h
index 7c6bfac..15d1d5c 100644
--- a/Include/fileobject.h
+++ b/Include/fileobject.h
@@ -30,6 +30,7 @@
 extern DL_IMPORT(int) PyFile_WriteObject(PyObject *, PyObject *, int);
 extern DL_IMPORT(int) PyFile_SoftSpace(PyObject *, int);
 extern DL_IMPORT(int) PyFile_WriteString(char *, PyObject *);
+extern DL_IMPORT(int) PyObject_AsFileDescriptor(PyObject *);
 
 #ifdef __cplusplus
 }