named-pipe | A cross-platform named-pipe implementation | Machine Learning library

No. At this time, the MaybeNullWhen/NotNullWhen attributes only work to signal that the null state of an out parameter depends on a bool return value.

There is currently no plan to allow the null state of a variable to depend on the value of an enum return value, for example.

There is also no plan to allow an interdependence between the elements of a tuple return value, i.e. the (object? result, bool ok) Method() pattern. If you are interested in such functionality getting added to the language, feel free to start a discussion on how it would work at https://github.com/dotnet/csharplang/discussions.

Based on documentation

To test the performance of the pipe, it is better that you convert the ExampleCLI project into two client and server projects and move the SomeClass model into a new class library. Your problem occurs when the model is serializable. That is why the server.ClientMessage, and client.ServerMessage are not called.

std::filesystem::exists("\\\\.\\pipe\\myPipe") returning ERROR_PIPE_BUSY means it is using CreateFile() to actually connect to the pipe. It is not unreasonable for an exists() implementation to attempt to open the requested file to check its existance.

Per the CreateFile() documentation:

If there is at least one active pipe instance but there are no available listener pipes on the server, which means all pipe instances are currently connected, CreateFile fails with ERROR_PIPE_BUSY.

Which means the pipe does technically exist, it is not ready to receive a new client at that moment.

In the link you provided, many of the solutions provided suggest using .NET's System.IO.Directory.GetFiles() method to iterate though the contents of "\\.\pipe\". This answer shows how that call translates into Win32 API calls using FindFirstFile() and FindNextFile(). You can easily do the same API calls in C++, eg:

From man parallel:

There is a a small issue when using GNU parallel as queue system/batch manager: You have to submit JobSlot number of jobs before they will start, and after that you can submit one at a time, and job will start immediately if free slots are available. Output from the running or completed jobs are held back and will only be printed when JobSlots more jobs has been started (unless you use --ungroup or --line-buffer, in which case the output from the jobs are printed immediately). E.g. if you have 10 jobslots then the output from the first completed job will only be printed when job 11 has started, and the output of second completed job will only be printed when job 12 has started.

In other words: The jobs are running. Output is delayed. It is easier to see if you instead of using echo in your example use touch unique-file-name.

The difference between your client and PHP is, that the client is linked against libmariadb (and is therefore able to load the auth_gssapi_plugin, while mysqli is either linked against libmysql or PHP's internal mysqlnd driver.

Beside Kerberos/GSSAPI MariaDB also provides ed25519 and pam authentication (via dialog plugin) which is not supported by libmysql and mysqlnd.

Building ext/mysqli against MariaDB Connector/C unfortunately doesn't work and recent pull requests which fixed that problem were rejected.

Since you can't use C++17, you'll need the WinAPI way of iterating over a directory. That's FindFirstFile / FindNextFile. Despite the name, that will also find pipes if you look in \\.\pipe\.

Consider using filename strings in your configuration file without the surrounding " marks.

For instance, general_log_file="A.log"

could be general_log_file=./general.log

to be descriptive of the log filename in Windows in your current datadir

There are others that do not need surrounding " marks.

The writer should close the file after it's done sending using file.Close(). Note that file.Close() may return error.

The pipe name you used on the C++ side is incorrect. It should be: "\\\\.\\pipe\\mynamedpipe".

Also, change the C# side to the following: