diff --git a/CHANGELOG.md b/CHANGELOG.md
index 48b4a484..96cc1c7e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+- Add FFI definition `PyObject_AsFileDescriptor` [#938](https://github.com/PyO3/pyo3/pull/938)
+
 ### Removed
 - Remove `ManagedPyRef` (unused, and needs specialization) [#930](https://github.com/PyO3/pyo3/pull/930)
 
diff --git a/src/ffi/fileobject.rs b/src/ffi/fileobject.rs
index d5cb6eeb..0bddd86a 100644
--- a/src/ffi/fileobject.rs
+++ b/src/ffi/fileobject.rs
@@ -15,6 +15,8 @@ extern "C" {
         arg7: *const c_char,
         arg8: c_int,
     ) -> *mut PyObject;
+    #[cfg_attr(PyPy, link_name = "PyPyFile_AsFileDescriptor")]
+    pub fn PyObject_AsFileDescriptor(arg1: *mut PyObject) -> c_int;
     #[cfg_attr(PyPy, link_name = "PyPyFile_GetLine")]
     pub fn PyFile_GetLine(arg1: *mut PyObject, arg2: c_int) -> *mut PyObject;
     #[cfg_attr(PyPy, link_name = "PyPyFile_WriteObject")]