使用 MMF 时获取文件读取权限

发布于 2024-11-16 04:30:22 字数 1154 浏览 6 评论 0原文

我有两个进程。一种是使用 .NET 4 MemoryMappedFiles 写入内存映射文件，另一种是使用 .NET 3.5 (MONO) 中的 FileStream 读取文件。当我获得许可时，一切正常，读取或写入文件没有问题。问题是要获得许可。

写入 MMF（写入器）：

MemoryMappedFile.CreateFromFile
                           (filenameToMap, FileMode.Create, "Something",
                           Marshal.SizeOf(objectToMap), MemoryMappedFileAccess.ReadWrite);

读取 MMF（读取器）：

new FileStream(filenameToMap, FileMode.Open, FileAccess.Read, FileShare.Delete | FileShare.ReadWrite);

首先启动写入器，然后启动读取器。

我使用这种幼稚的方法对其进行了测试：

while (true)
        {
            try
            {
                  new FileStream(mapPath + "map.mp", FileMode.Open, FileAccess.Read, FileShare.Delete | FileShare.ReadWrite);
                    break;
            }
            catch { }
        }

大约 10 秒后，读者通常会获得许可，一切都会顺利进行。如果我捕获异常，它会抛出：

IOException：路径上的共享冲突 C:\路径位于 System.IO.FileStream..ctor （System.String路径，FileMode模式， FileAccess 访问、FileShare 共享、 Int32 bufferSize，布尔匿名， FileOptions 选项）[0x00000] 中 :0

知道为什么这两个进程从一开始就不能正确共享文件吗？

原文

I have two processes. One writing in a memory mapped file using .NET 4 MemoryMappedFiles and the other reading the file using FileStream in .NET 3.5 (MONO). Everything works fine when I get the permission, no problem reading or writing the file. The problem is to obtain a permission.

Writing MMF (the Writer):

MemoryMappedFile.CreateFromFile
                           (filenameToMap, FileMode.Create, "Something",
                           Marshal.SizeOf(objectToMap), MemoryMappedFileAccess.ReadWrite);

Reading MMF (the Reader):

new FileStream(filenameToMap, FileMode.Open, FileAccess.Read, FileShare.Delete | FileShare.ReadWrite);

First I start the Writer, then the Reader.

I tested it using this naive approach:

while (true)
        {
            try
            {
                  new FileStream(mapPath + "map.mp", FileMode.Open, FileAccess.Read, FileShare.Delete | FileShare.ReadWrite);
                    break;
            }
            catch { }
        }

After roughly 10 seconds, the Reader usually gets permission and everything runs smooth. If I would catch the exception, it would throw:

IOException: Sharing violation on path
C:\path at
System.IO.FileStream..ctor
(System.String path, FileMode mode,
FileAccess access, FileShare share,
Int32 bufferSize, Boolean anonymous,
FileOptions options) [0x00000] in
:0

Any idea why these two processes don't share the file properly from beginning?

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