If wchar is not included in ncurses, mc 4.8.26 fails to compile.

[mrbump]

With the introduction of shadows in mc (which are nice) on platforms that support them with the following commit - ​https://github.com/MidnightCommander/mc/commit/8b4386df83ab5a525f0568113fe1e53d362f433e.patch and Ticket #4120: draw shadows for dialog boxes and menus.

Mc 4.8.26 fails to compile on LibreELEC. - ​https://libreelec.tv/ - the Tagline being Just enough OS for KODI

We use --disable-widec in the ncurses build, ​https://github.com/LibreELEC/LibreELEC.tv/blob/master/packages/devel/ncurses/package.mk

Reverting the whole patch fixes the compile, but it would be ideal to use alternatives or limit shadows if wchar is not available.

Results of the failed compile

./.libs/libinternal.a(tty-ncurses.o):tty-ncurses.c:function tty_colorize_area: error: undefined reference to 'mvin_wchnstr'
./.libs/libinternal.a(tty-ncurses.o):tty-ncurses.c:function tty_colorize_area: error: undefined reference to 'getcchar'
./.libs/libinternal.a(tty-ncurses.o):tty-ncurses.c:function tty_colorize_area: error: undefined reference to 'setcchar'
./.libs/libinternal.a(tty-ncurses.o):tty-ncurses.c:function tty_colorize_area: error: undefined reference to 'mvadd_wchnstr'

[mrbump]

The code that has the wchar is

+++ b/lib/tty/tty-ncurses.c
@@ -533,6 +550,38

/* --------------------------------------------------------------------------------------------- */

+void
+tty_colorize_area (int y, int x, int rows, int cols, int color)
+{
+    cchar_t *ctext;
+    wchar_t wch[10];   /* TODO not sure if the length is correct */
+    attr_t attrs;
+    short color_pair;
+
+    if (!use_colors || !tty_clip (&y, &x, &rows, &cols))
+        return;
+
+    tty_setcolor (color);
+    ctext = g_malloc (sizeof (cchar_t) * (cols + 1));
+
+    for (int row = 0; row < rows; row++)
+    {
+        mvin_wchnstr (y + row, x, ctext, cols);
+
+        for (int col = 0; col < cols; col++)
+        {
+            getcchar (&ctext[col], wch, &attrs, &color_pair, NULL);
+            setcchar (&ctext[col], wch, attrs, color, NULL);
+        }
+
+        mvadd_wchnstr (y + row, x, ctext, cols);

[mrbump]

Original change that created the issue #4102

[andrew_b]

Fixed as #4181.

[mrbump]

Whilst that patch fixed MacOS it doesn’t fix LibreELEC as wide char is not included. I had tested that patch as I had compiled against master ​https://github.com/MidnightCommander/mc/commits/master . If you could suggest a direction of what would be acceptable to the mc team, I would be happy to develop a code fix. As in tty-slang I see that tty_colorize_area is essentially a noop.

Should I write a —without-wchar configure option?

[zaytsev]

How is it possible that LibreELEC doesn't have a definition of wchar_t? Kodi itself seems to use it all over the place... How do you solve this problem?

To me it seems that of course you do have wchar_t, only for some reason we cannot understand yet you compile ncurses with --disable-widec, so even though mc does compile against ncurses, according to your log the linking fails, because mvadd_wchnstr function cannot be found. Just compile ncurses --enable-widec to solve this problem if you can. I would be surprised if mc interface will be rendered correctly if you compile against ncurses with --disable-widec anyways.

[andrew_b]

Please test the attached patch.

[andrew_b]

ping

[andrew_b]

@mrbump, please let me know if this patch works or not.

[mrbump]

Hi @andrew_b

we just pulled the patch into 4.8.27. And removed the previous revert patch. All works as expected. ​https://github.com/LibreELEC/LibreELEC.tv/pull/5562

Regards
Rudi

[andrew_b]

Branch: 4200_ncurses_disable_widec
changeset:e7bbf72544ab62db9c92bfe7bd1155227e78c621

[andrew_b]

Merged to master: [375f2a764dc0d276e98cdcf0e9f890f41250c041].