- Issue #6939: Fix file I/O objects in the `io` module to keep the original
  file position when calling `truncate()`.  It would previously change the
  file position to the given argument, which goes against the tradition of
  ftruncate() and other truncation APIs.  Patch by Pascal Chambon.
diff --git a/Modules/_io/iobase.c b/Modules/_io/iobase.c
index 3732f46..3344847 100644
--- a/Modules/_io/iobase.c
+++ b/Modules/_io/iobase.c
@@ -102,8 +102,8 @@
 PyDoc_STRVAR(iobase_truncate_doc,
     "Truncate file to size bytes.\n"
     "\n"
-    "Size defaults to the current IO position as reported by tell().  Return\n"
-    "the new size.");
+    "File pointer is left unchanged.  Size defaults to the current IO\n"
+    "position as reported by tell().  Returns the new size.");
 
 static PyObject *
 iobase_truncate(PyObject *self, PyObject *args)