Some man pages.

man/man3/dup.3

@@ -25,18 +25,14 @@ will use
 for the new file descriptor
 (closing any old file associated with
 .IR newfd ).
-File descriptors are allocated dynamically,
-so to prevent unwarranted growth of the file descriptor table,
-.I dup
-requires that
-.I newfd
-be no greater than 20 more than the highest file descriptor ever used by
-the program.
 .SH SOURCE
-.B /usr/local/plan9/src/libc/9syscall
-.SH SEE ALSO
-.IR intro (3),
-.IR dup (3)
+.B /usr/local/plan9/src/lib9/dup.c
 .SH DIAGNOSTICS
 Sets
 .IR errstr .
+.SH BUGS
+.I Dup
+is a macro for
+.I p9dup
+to avoid name conflicts with the Unix function; see
+.IR intro (3).