ANSI Common Lisp   2 Syntax   2.4 Standard Macro Characters   2.4.8 Sharpsign

2.4.8.14 Sharpsign P

#P reads a following object, which must be a string.

#P<<expression>> is equivalent to #.(parse-namestring '<<expression>>), except that #P is not affected by *read-eval*.

For information on how the Lisp printer prints pathnames, see Section 22.1.3.11 Printing Pathnames.