-\fBTRUE\fR or \fBFALSE\fR; \fIbf\fR is always of type \fBbool\fR. The
-variables \fIch\fR and \fIattrs\fR below are always of type
-\fBchtype\fR. The types \fBWINDOW\fR, \fBSCREEN\fR, \fBbool\fR, and
-\fBchtype\fR are defined in \fB<curses.h>\fR. The type \fBTERMINAL\fR
-is defined in \fB<term.h>\fR. All other arguments are integers.
+\fBTRUE\fR or \fBFALSE\fR; \fIbf\fR is always of type \fBbool\fR.
+Most of the data types used in the library routines,
+such as \fBWINDOW\fR, \fBSCREEN\fR, \fBbool\fR, and \fBchtype\fR
+are defined in \fB<curses.h>\fR.
+Types used for the terminfo routines such as
+\fBTERMINAL\fR are defined in \fB<term.h>\fR.
+.PP
+This manual page describes functions which may appear in any configuration
+of the library.
+There are two common configurations of the library:
+.RS 3
+.TP 5
+.I ncurses
+the "normal" library, which handles 8-bit characters.
+The normal (8-bit) library stores characters combined with attributes
+in \fBchtype\fP data.
+.IP
+Attributes alone (no corresponding character) may be stored in \fBchtype\fP
+or the equivalent \fBattr_t\fP data.
+In either case, the data is stored in something like an integer.
+.IP
+Each cell (row and column) in a \fBWINDOW\fP is stored as a \fBchtype\fP.
+.TP 5
+.I ncursesw
+the so-called "wide" library, which handles multibyte characters
+(see the section on \fBALTERNATE CONFIGURATIONS\fP).
+The "wide" library includes all of the calls from the "normal" library.
+It adds about one third more calls using data types which store
+multibyte characters:
+.RS 5
+.TP 5
+.B cchar_t
+corresponds to \fBchtype\fP.
+However it is a structure, because more data is stored than can fit into
+an integer.
+The characters are large enough to require a full integer value \- and there
+may be more than one character per cell.
+The video attributes and color are stored in separate fields of the structure.
+.IP
+Each cell (row and column) in a \fBWINDOW\fP is stored as a \fBcchar_t\fP.
+.TP 5
+.B wchar_t
+stores a "wide" character.
+Like \fBchtype\fP, this may be an integer.
+.TP 5
+.B wint_t
+stores a \fBwchar_t\fP or \fBWEOF\fP \- not the same, though both may have
+the same size.
+.RE
+.IP
+The "wide" library provides new functions which are analogous to
+functions in the "normal" library.
+There is a naming convention which relates many of the normal/wide variants:
+a "_w" is inserted into the name.
+For example, \fBwaddch\fP becomes \fBwadd_wch\fP.
+.RE
+.PP
+.\"