X-Git-Url: https://ncurses.scripts.mit.edu/?p=ncurses.git;a=blobdiff_plain;f=ncurses%2Fbase%2Flib_addch.c;h=0da27e0b424bb2d6c73bb43202f09836a3eeb606;hp=7c9e407c6aa6495fccde7a5982607089964c65c4;hb=fae162795e065e5901068152e91f2962b6b247f3;hpb=b724cdc89cf31757ab43262ecefe5242b0edc450

diff --git a/ncurses/base/lib_addch.c b/ncurses/base/lib_addch.c
index 7c9e407c..0da27e0b 100644
--- a/ncurses/base/lib_addch.c
+++ b/ncurses/base/lib_addch.c
@@ -37,7 +37,7 @@
 #include <curses.priv.h>
 #include <ctype.h>
 
-MODULE_ID("$Id: lib_addch.c,v 1.135 2021/01/31 00:42:53 tom Exp $")
+MODULE_ID("$Id: lib_addch.c,v 1.136 2021/02/13 22:33:05 tom Exp $")
 
 static const NCURSES_CH_T blankchar = NewChar(BLANK_TEXT);
 
@@ -208,6 +208,20 @@ _nc_build_wch(WINDOW *win, ARG_CH_T ch)
     WINDOW_EXT(win, addch_x) = x;
     WINDOW_EXT(win, addch_y) = y;
 
+    /*
+     * If the background character is a wide-character, that may interfere with
+     * processing multibyte characters in this function.
+     */
+    if (!is8bits(CharOf(CHDEREF(ch)))) {
+	if (WINDOW_EXT(win, addch_used) != 0) {
+	    /* discard the incomplete multibyte character */
+	    WINDOW_EXT(win, addch_used) = 0;
+	    TR(TRACE_VIRTPUT,
+	       ("Alert discarded incomplete multibyte"));
+	}
+	return 1;
+    }
+
     init_mb(state);
     buffer[WINDOW_EXT(win, addch_used)] = (char) CharOf(CHDEREF(ch));
     WINDOW_EXT(win, addch_used) += 1;