.\"***************************************************************************
-.\" Copyright (c) 2001-2017,2019 Free Software Foundation, Inc. *
+.\" Copyright 2019,2020 Thomas E. Dickey *
+.\" Copyright 2001-2015,2017 Free Software Foundation, Inc. *
.\" *
.\" Permission is hereby granted, free of charge, to any person obtaining a *
.\" copy of this software and associated documentation files (the *
.\" authorization. *
.\"***************************************************************************
.\"
-.\" $Id: curs_add_wch.3x,v 1.25 2019/10/27 00:07:13 tom Exp $
+.\" $Id: curs_add_wch.3x,v 1.28 2020/10/17 23:10:38 tom Exp $
.TH curs_add_wch 3X ""
.ie \n(.g .ds `` \(lq
.el .ds `` ``
.B "int mvadd_wch( int \fIy\fP, int \fIx\fP, const cchar_t *\fIwch\fB );"
.br
.B "int mvwadd_wch( WINDOW *\fIwin\fP, int \fIy\fP, int \fIx\fP, const cchar_t *\fIwch\fB );"
-.br
+.sp
.B "int echo_wchar( const cchar_t *\fIwch\fB );"
.br
.B "int wecho_wchar( WINDOW *\fIwin\fP, const cchar_t *\fIwch\fB );"
.PP
All routines 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
+.bP
+if the window pointer is null or
+.bP
+if it is not possible to add a complete character in the window.
+.PP
+The latter may be due to different causes:
+.bP
+If \fBscrollok\fR is not enabled,
+writing a character at the lower right margin succeeds.
+However, an error is returned because
+it is not possible to wrap to a new line
+.bP
+If an error is detected when converting a multibyte character to a sequence
+of bytes,
+or if it is not possible to add all of the resulting bytes in the window,
+an error is returned.
+.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.