If
.I c
is a uppercase letter,
-.BR toupper ()
+.BR tolower ()
returns its lowercase equivalent,
if a lowercase representation exists in the current locale.
Otherwise, it returns
.BR towupper (3),
.BR locale (7)
.SH COLOPHON
-This page is part of release 3.64 of the Linux
+This page is part of release 3.65 of the Linux
.I man-pages
project.
A description of the project,