How does intellij-lsp connect to a language server?

[observant2]

I'm trying to build a language server. It reads from stdin and writes to stdout. To debug I just read from stdin and write to a file.

So I just compiled a program that reads a line and writes it to a file (endless loop). When I put this program's path as executable in the settings of intellij-lsp, then it says after 10 secs that the language server couldn't initialize. That's okay. But also the file that has been created is empty. Is there a misunderstanding and intellij-lsp doesn't communicate via stdin/stdout?

[observant2]

Okay, now on Linux it works. It seems to be a Windows related problem. I have to skim through the code to see where the problem lies, but that's good to know either way.