Double line box_drawing characters in terminal

Question

This piece of code in wikipedia:

$ char=( 6a 6b 6c 6d 6e 71 74 75 76 77 78 )
$ for i in ${char[*]}; do printf "0x$i \x$i \e(0\x$i\e(B\n"; done

includes one-line box-drawing characters. Are there double-line box-drawing characters in terminal?

For example how can I print the character "╢".

I'll use them in a C++ program like this:

#include <stdio.h>

int main()
{
    printf("\e(0\x6a\e(B "); // 188
    printf("\e(0\x6b\e(B "); // 187
    printf("\e(0\x6c\e(B "); // 201
    printf("\e(0\x6d\e(B "); // 200
    printf("\e(0\x6e\e(B "); // 206
    printf("\e(0\x71\e(B "); // 205
    printf("\e(0\x74\e(B "); // 204
    printf("\e(0\x75\e(B "); // 185
    printf("\e(0\x76\e(B "); // 202
    printf("\e(0\x77\e(B "); // 203
    printf("\e(0\x78\e(B "); // 186
}

Answer 1

What charset do you have your terminal set to use? If you are still using ASCII, you don't have double-line box-drawing characters available to you. If you are using UTF-8, you can send out the UTF-8 character sequence for these characters. I believe printf("╢") will work if you compiler accepts UTF-8 in the source code, e.g. gcc with -finput-charset=UTF-8.

Answer 2

Some of the comments suggested ncurses as a possible solution. There are pros/cons to that:

• ncurses is useful for drawing text while moving about the screen (either full-screen, or a full-line using filter). OP's example prints a fragment of a single line, and the discussion gave no clues whether this was a typical use, or part of something more elaborate.
• ncurses has a repertoire of symbols for commonly-used lines. The particular example shown (a mixed single-width and double-width symbol) is not in that list, i.e., Unicode Character 'BOX DRAWINGS VERTICAL DOUBLE AND LEFT SINGLE' (U+2562)

ncurses accepts UTF-8 strings, and keeps track of the current position, but attaches no particular significance to box-drawing symbols not in its repertoire. Since 2009 (after the 5.7 release), it has symbols for double- and thick-linedrawing, but those are far from the full set of Unicode box-drawing graphics since they are not mixed. Here are some screenshots from the ncurses test-program showing the predefined symbols that ncurses supports: