I consider the linux-man-pages project (usually simply "man-pages" in most linux distributions) to be the single best reference manual for UNIX C programming. I

I consider the linux-man-pages project (usually simply "man-pages" in most linux distributions) to be the single best reference manual for UNIX C programming. It has extensive descriptions, examples, warns about libc/platform differences, and allows discovery of new/similar functions through the SEE ALSO section at the end of the page. https://man7.org/linux/man-pages/dir_section_3.html https://man7.org/linux/man-pages/dir_section_3.html