diff --git a/Doc/c-api/buffer.rst b/Doc/c-api/buffer.rst
index ec44a9966d6..d14fd80c282 100644
--- a/Doc/c-api/buffer.rst
+++ b/Doc/c-api/buffer.rst
@@ -289,7 +289,7 @@ Buffer related functions
    given shape with the given number of bytes per element.
 
 
-.. cfunction:: int PyBuffer_FillInfo(Py_buffer *view, void *buf, Py_ssize_t len, int readonly, int infoflags)
+.. cfunction:: int PyBuffer_FillInfo(Py_buffer *view, PyObject *obj, void *buf, Py_ssize_t len, int readonly, int infoflags)
 
    Fill in a buffer-info structure, *view*, correctly for an exporter that can
    only share a contiguous chunk of memory of "unsigned bytes" of the given