Comment by Almondsetat
1 hour ago
Have you ever seen a programmer who really understands C going to stackoverflow every time they have to use an fopen()? Memorization is part of understanding. You cannot understand something without it being readily available in your head
I wrote a long answer, but I realised that even advanced C users are unlikely to have memorised every possible value of errno and what they all mean when fopen errors. There's just no point as you can easily look it up. You can understand that there is a maximum allowable number of opened files without remembering what exact value errno will have in this case.