My goal is to write to and read same file at same time. I cannot understand why File.Open(fileName, FileMode.Open, FileAccess.Read, FileShare.Read) fails because it is being used by another process. The file is created by my code and I didn't set any special attributes. Tried in both .net framework 4.8 and .net6 console apps.

        static void Main(string[] args)
        {
            const string fileName = "TestFile.txt";
            try
            {
                FileStream ws = File.Open(fileName, FileMode.OpenOrCreate, FileAccess.Write, FileShare.Read);
                Console.WriteLine("ws ok");
            }
            catch (Exception ex)
            {
                Console.WriteLine($"ws {ex.Message}");
            }

            try
            {
                FileStream rs = File.Open(fileName, FileMode.Open, FileAccess.Read, FileShare.Read);
                Console.WriteLine("rs ok");
            }
            catch (Exception ex)
            {
                Console.WriteLine($"rs {ex.Message}");
                //rs The process cannot access the file 'debugpath\TestFile.txt' because it is being used by another process.
            }
            //stream close omited
            Console.ReadKey();
        }

Have read the docs FileShare Enum but cannot find any reason. Doesn't FileShare.Read mean share the file or stream with others(threads, processes) to read?

Could anyone explain the reason, and give the correct way to read the file?