bpo-2122: Make mmap.flush() behave same on all platforms (GH-8692)

Previously, its behavior was platform-dependent and there was no error checking
under Windows.

1 files changed, 7 insertions, 4 deletions

diff --git a/Modules/mmapmodule.c b/Modules/mmapmodule.c
index 27030db..af9cd7e 100644
--- a/Modules/mmapmodule.c
+++ b/Modules/mmapmodule.c
@@ -569,18 +569,21 @@ mmap_flush_method(mmap_object *self, PyObject *args)
     }
 
     if (self->access == ACCESS_READ || self->access == ACCESS_COPY)
-        return PyLong_FromLong(0);
+        Py_RETURN_NONE;
 
 #ifdef MS_WINDOWS
-    return PyLong_FromLong((long) FlushViewOfFile(self->data+offset, size));
+    if (!FlushViewOfFile(self->data+offset, size)) {
+        PyErr_SetFromWindowsErr(GetLastError());
+        return NULL;
+    }
+    Py_RETURN_NONE;
 #elif defined(UNIX)
-    /* XXX semantics of return value? */
     /* XXX flags for msync? */
     if (-1 == msync(self->data + offset, size, MS_SYNC)) {
         PyErr_SetFromErrno(PyExc_OSError);
         return NULL;
     }
-    return PyLong_FromLong(0);
+    Py_RETURN_NONE;
 #else
     PyErr_SetString(PyExc_ValueError, "flush not supported on this system");
     return NULL;