c - What is the difference between stdin and STDIN_FILENO?

Question

What is the practical difference, if any, between stdin and STDIN_FILENO in C?

Answer 1

The interface. Like everyone else has said, stdin is a FILE * as defined by the standard c library. You can use some of the higher level interfaces like fread, fwrite, and fprintf. On the other hand, STDIN_FILENO is just a file descriptor (almost certainly 0). This uses a slight lower level interface through the likes of read and write.