@mhoye I've been saying this for decades. The problem starts with:

#define EPERM 1 /* Operation not permitted */

What operation? On what object? Due to what context or user identity? Who do have to ask for permission?

Continues:

#define ENOENT 2 /* No such file or directory */

Is it a file or a directory? Which part of my pathname failed? Is it because a directory isn't searchable or just doesn't exist?

The operating system clearly knew all these facts, but returned only -1 and an errno