CODEWITHSUNDEEP
c#.netmemory-mapped-files
user978122
user978122

Reputation: 5761

Memory-mapped files -> Checking for duplicate file names

Working on an app that will use memory-mapped files for some inter-(or is it intra?)application communication, and I want to make sure when I randomly generate a memory-mapped memory-only file, I don't accidentally generate or get a duplicate that already exists (that ultra-rare case when the planets align and something like that might happen). Any ideas on how to prevent that? System.IO.MemoryMappedFiles does not appear to have a File.Exists() method...I guess I could try OpenOrCreate() and deal with any access violations, etc., but this would be getting nasty quick.

Upvotes: 0

Views: 716

Answers (3)

Erik Funkenbusch
Erik Funkenbusch

Reputation: 93434

First, you can prevent a naming conflict by using a unique name for your file, such as your company name, or your application name, or both. No other app is going to have those in the file name. If you're worried about two copies of the same app, then you can simply open the file in Create only mode, rather than Create or Open.

Upvotes: 0

WithMetta
WithMetta

Reputation: 26

From: Programming Memory-Mapped Files with the .NET Framework - CodeProject.com

static void Main(string[] args)
{
    string name = "NetMMFSingle";

    // Create named MMF
    try
    {
        var mmf = MemoryMappedFile.CreateNew(name, 1);
    } catch
    {
        Console.WriteLine("Instance already running...");
        return;
    }

    ConsoleKeyInfo key = Console.ReadKey();

    // Your real code follows...
}

Upvotes: 1

Henk Holterman
Henk Holterman

Reputation: 273229

Using File.Exists() wouldn't be concurrency-safe anyway.

The best thing to do: base a Filename on a Guid.

Upvotes: 2

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