fpathconf.3: Add an errors section

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man3/fpathconf.3

@@ -195,6 +195,50 @@ the corresponding value that was described to the application in
 or
 .I <limits.h>
 when the application was compiled.
+.SH ERRORS
+.TP
+.B EACCES
+.RB ( pathconf ())
+Search permission is denied for one of the directories in the path prefix of
+.IR path .
+.TP
+.B EBADF
+.RB ( fpathconf ())
+.I fd
+is not a valid file descriptor.
+.TP
+.B EINVAL
+.I name
+is invalid.
+.TP
+.B EINVAL
+The implementation does not support an association of
+.I name
+with the specified file.
+.TP
+.B ELOOP
+.RB ( pathconf ())
+Too many symbolic links were encountered while resolving
+.IR path .
+.TP
+.B ENAMETOOLONG
+.RB ( pathconf ())
+.I path
+is too long.
+.TP
+.B ENOENT
+.RB ( pathconf ())
+A component of
+.I path
+does not exist, or
+.I path
+is an empty string.
+.TP
+.B ENOTDIR
+.RB ( pathconf ())
+A component used as a directory in
+.I path
+is not in fact a directory.
 .SH ATTRIBUTES
 For an explanation of the terms used in this section, see
 .BR attributes (7).