windows - Windows 中的 msync 等效项

Question

Windows 中的 msync [unix sys call] 等价物是什么？我正在寻找 C、C++ 空间中的 MSDN api。有关 msync 的更多信息，请访问 http://opengroup.org/onlinepubs/007908799/xsh/msync.html。

Answer 1

FlushViewOfFile

查看 Python 2.6 mmapmodule.c 以获取正在使用的 FlushViewOfFile 和 msync 的示例:

/*
 /  Author: Sam Rushing <rushing@nightmare.com>
 /  Hacked for Unix by AMK
 /  $Id: mmapmodule.c 65859 2008-08-19 17:47:13Z thomas.heller $

 / Modified to support mmap with offset - to map a 'window' of a file
 /   Author:  Yotam Medini  yotamm@mellanox.co.il
 /
 / mmapmodule.cpp -- map a view of a file into memory
 /
 / todo: need permission flags, perhaps a 'chsize' analog
 /   not all functions check range yet!!!
 /
 /
 / This version of mmapmodule.c has been changed significantly
 / from the original mmapfile.c on which it was based.
 / The original version of mmapfile is maintained by Sam at
 / ftp://squirl.nightmare.com/pub/python/python-ext.
*/

static PyObject *
mmap_flush_method(mmap_object *self, PyObject *args)
{
    Py_ssize_t offset = 0;
    Py_ssize_t size = self->size;
    CHECK_VALID(NULL);
    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;
    }
#ifdef MS_WINDOWS
    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)) {
        PyErr_SetFromErrno(mmap_module_error);
        return NULL;
    }
    return PyInt_FromLong(0);
#else
    PyErr_SetString(PyExc_ValueError, "flush not supported on this system");
    return NULL;
#endif
}

更新:我认为您不会在 win32 映射文件 API 中找到完全相同的东西。 FlushViewOfFile API 没有同步风格(可能是因为缓存管理器的可能影响)。如果需要精确控制何时将数据写入磁盘，也许您可​​以在创建映射文件的句柄时将 FILE_FLAG_NO_BUFFERING 和 FILE_FLAG_WRITE_THROUGH 标志与 CreateFile API 一起使用？