memory-mapped-files

问题 I am looking to take use of a memory mapped file from Guild Wars 2, which is designed to link into Mumble for positional audio. The file contains information on the characters coordinates and other useful information. I have been able to access the coordinate information using this script, import mmap import struct last=[] while True: shmem = mmap.mmap(0, 20, "MumbleLink", mmap.ACCESS_READ) coord=struct.unpack("IL3f", shmem)[2:5] shmem.close() if last!=coord: print(coord) last = coord X =

问题 I am trying to use combination of functions CreateFileMapping , MapViewOfFile, FlushViewOfFile. the total buffer size is more than the mapped view. example buffer is 50KB. and mapped view is 2KB. in such scenario, i want to write the total buffer to a physical file, using the above function. First part i am able to write to file. but the remaining part how to write to file. I mean, how to move to next page and write the next part of data. #define MEM_UNIT_SIZE 100 -first module...Memory map

问题 UPDATE 2 / TL;DR Is there some way to prevent dirty pages from a windows temporary delete-on-close file being flushed as a result of closing memory maps opened on these files. Yes. If you do not need to do anything with the files themselves after their initial creation and you implement some naming conventions, this is possible through the strategy explained in this answer. Note: I am still quite interested in finding out the reasons for why there is so much difference in the behavior

问题 I am searching for fast writing a file using C++ and boost library. And I would like to use memory mapped file. But Almost all example is about reading. Working is very simple. There is a string array. The array elements is about 2 millions. ofstream outFile("text.txt"); for (int i = 0; i < 2000000; ++i) { outFile << strArray[i] << "\n"; } outFile.close(); How can I do it using memory mapped file? Where can I find writing file using memory mapped file? Thank you for your concerning. 回答1: You

问题 I'd like to know if anyone tried new .NET 4.0 Memory Mapped Files features? I know that they are as old as OS but native handling in .NET is new. Has anyone been able to test this and say something about performance? I'm quite interested in access time to random parts of binary file, write speed and so on. Also performance comparsion to native WinAPI MMF would be nice. Thanks! 回答1: Memory mapped files in .NET 4.0 (in the new System.IO.MemoryMappedFiles namespace) simply wrap the Win32 API for

问题 I'm trying to share a struct similar to the following example: typedef struct { int *a; int b; int c; } example; I'm trying to share this struct between processes, the problem that I find is that when I initialize 'a' with malloc, I won't be able to access the array from within the second process. Is it possible to add this dynamic array to the memory mapped file? 回答1: You can have it as typedef struct { int b; int c; int asize; // size of "a" in bytes - not a number of elements int a[0]; }

问题 Can we merge two memory mapped files? if so the how? if not then why not? 回答1: So here are my first experiences with MemoryMappedFiles, give it a try: String f1Path = @"C:\Temp\Test1.txt"; String f2Path = @"C:\Temp\Test2.txt"; byte[] buffer; int offset; int length; using (FileStream f1ReadStream = new FileStream(f1Path, FileMode.Open, FileAccess.Read)) { offset = (int)f1ReadStream.Length; } using (FileStream f2ReadStream = new FileStream(f2Path, FileMode.Open, FileAccess.Read)) { length =

问题 using MMF and C# I was creating a Shared Memory between 2 processes. my aim is to create it as a global say 4000 byte length and create partitions so Main proj is "MainProj" will start the MMF Named "$AppName$_sharedMMF" then "Debugger Proj" will Access that "$AppName$_sharedMMF" so the accessor positions are: MainProj->Debugger : readAddr = 0 , writeAddr = 250 Debbugger->MainProj : reafAddr = 250, writeAddr = 0 then the third executable in my solution will be //setter getter MainProj-

问题 Is there a way to check how many views have been mapped on to a memory mapped file on Windows? Something like the equivalent of shmctl(... ,IPC_STAT,...) on Linux? 回答1: I had the same need to access the number of shared views. So I created this question: Accessing the number of shared memory mapped file views (Windows) You may find a solution that suits your needs there. As per Scath comment, I am going to add here the proposed solution, although merit should go to eryksun and RbMm. Making

问题 Is there a way to store and load raw image data on disk in iOS in order to save time and memory on decompression and reduce app's dirty memory footprint? Paul Haddad has been hinting to something like this and I understand that this technique is used for efficient game texture loading with OpenGL. My use case if for user supplied full screen wallpaper, that is always displayed in the background. Currently I save it to PNG and load it during app startup. This wastes memory and CPU for