7.19 Input/output <stdio.h> (pdf page 274)

  BUFSIZ

  which expands to an integer constant expression that is the size of
  the buffer used by the setbuf function;

  EOF

  which expands to an integer constant expression, with type int and a
  negative value, that is returned by several functions to indicate
  end-of-file, that is, no more input from a stream;