[New-bugs-announce] [issue2122] mmap.flush does not check for errors on windows

Ralf Schmitt report at bugs.python.org
Fri Feb 15 14:20:03 CET 2008

New submission from Ralf Schmitt:

mmap.flush returns the result of the call to FlushViewOfFile as an
integer, and does not check for errors. On unix it does check for
errors. The function should return None and raise an exception if an
error occurs...
This bug can lead to data loss...

Here's the current version of that function:

static PyObject *
mmap_flush_method(mmap_object *self, PyObject *args)
	Py_ssize_t offset = 0;
	Py_ssize_t size = self->size;
	if (!PyArg_ParseTuple(args, "|nn:flush", &offset, &size))
		return NULL;
	if ((size_t)(offset + size) > self->size) {
		PyErr_SetString(PyExc_ValueError, "flush values out of range");
		return NULL;
	return PyInt_FromLong((long) FlushViewOfFile(self->data+offset, size));
#elif defined(UNIX)
	/* XXX semantics of return value? */
	/* XXX flags for msync? */
	if (-1 == msync(self->data + offset, size, MS_SYNC)) {
		return NULL;
	return PyInt_FromLong(0);
	PyErr_SetString(PyExc_ValueError, "flush not supported on this system");
	return NULL;

components: Library (Lib)
messages: 62427
nosy: schmir
severity: major
status: open
title: mmap.flush does not check for errors on windows
type: behavior
versions: Python 2.5, Python 2.6, Python 3.0

Tracker <report at bugs.python.org>

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