ls is as specified in ISO POSIX (2003), but with differences listed below.
If the file is a character special or block special file, the size of the file shall be replaced with two unsigned numbers in the format "%u, %u", representing the major and minor device numbers associated with the special file.
The LSB does not specify the meaning of the major and minor devices numbers.
in addition to ISO POSIX (2003) behavior of printing a slash for a directory, ls -p may display other characters for other file types.
Certain aspects of the pattern matching notation are optional; see Internationalization and Pattern Matching Notation.