Fixed documentation of functions with const char* arguments.
diff --git a/Doc/c-api/marshal.rst b/Doc/c-api/marshal.rst
index 9ea0aaa..a6d0f46 100644
--- a/Doc/c-api/marshal.rst
+++ b/Doc/c-api/marshal.rst
@@ -88,7 +88,7 @@
:exc:`TypeError`) and returns *NULL*.
-.. c:function:: PyObject* PyMarshal_ReadObjectFromString(char *string, Py_ssize_t len)
+.. c:function:: PyObject* PyMarshal_ReadObjectFromString(const char *string, Py_ssize_t len)
Return a Python object from the data stream in a character buffer
containing *len* bytes pointed to by *string*.