-These routines copy \fIchstr\fR into the window image structure at and after
-the current cursor position. The four routines with \fIn\fR as the last
-argument copy at most \fIn\fR elements, but no more than will fit on the line.
-If \fBn\fR=\fB-1\fR then the whole string is copied, to the maximum number of
-characters that will fit on the line.
-
-The window cursor is \fInot\fR advanced, and these routines work faster than
-\fBwaddnstr\fR. On the other hand, they don't perform any kind of checking
-(such as for the newline, backspace, or carriage return characters), they don't
-advance the current cursor position, they don't expand other control characters
-to ^-escapes, and they truncate the string if it crosses the right margin,
-rather then wrapping it around to the new line.
-
-.SH RETURN VALUES
-All routines return the integer \fBERR\fR upon failure and \fBOK\fR on success
-(the SVr4 manuals specify only "an integer value other than \fBERR\fR") upon
-successful completion, unless otherwise noted in the preceding routine
-descriptions.
+These functions copy the (null-terminated)
+\fIchstr\fR array
+into the window image structure
+starting at the current cursor position.
+The four functions with \fIn\fR as the last
+argument copy at most \fIn\fR elements,
+but no more than will fit on the line.
+If \fBn\fR=\fB\-1\fR then the whole array is copied,
+to the maximum number of characters that will fit on the line.
+.PP
+The window cursor is \fInot\fR advanced.
+These functions work faster than \fBwaddnstr\fR.
+On the other hand:
+.bP
+they do not perform checking
+(such as for the newline, backspace, or carriage return characters),
+.bP
+they do not advance the current cursor position,
+.bP
+they do not expand other control characters to ^-escapes, and
+.bP
+they truncate the string if it crosses the right margin,
+rather than wrapping it around to the new line.
+.SH RETURN VALUE
+All functions return the integer \fBERR\fR upon failure and \fBOK\fR on success.
+.PP
+X/Open does not define any error conditions.
+This implementation returns an error
+if the window pointer is null.
+.PP
+Functions with a "mv" prefix first perform a cursor movement using
+\fBwmove\fP, and return an error if the position is outside the window,
+or if the window pointer is null.