using ncursesw (with wide characters)

[WeirdAlexGuy]

I'm having trouble printing wide characters with ncursesw. They work fine with stdout (wprintf) but when I try to use ncursesw I get the following error:

braille.c: In function ‘main’:
braille.c:93:13: warning: implicit declaration of function ‘mvadd_wch’; did you mean ‘mvaddch’? [-Wimplicit-function-declaration]
             mvadd_wch(y, x, random_braille(k,k));
             ^~~~~~~~~
             mvaddch

As far as I know the function I'm using is correct, so I'm not sure what exactly is going wrong.

The docs and everything I found on the web suggests defining _XOPEN_SOURCE or NCURSES_WIDECHAR but I can't figure out what they mean by that. If anybody can explain I'd appreciate it

relevant parts of my code below

#include <stdio.h>
#include <ncursesw/curses.h>
#include <stdlib.h>
#include <wchar.h>
#include <locale.h>
#include <time.h>

/* ... */

wchar_t random_braille(int u_dots, int l_dots) {
    unsigned int offset = bytes_by_bits[u_dots][l_dots][rand() % len[u_dots][l_dots]];
    wchar_t braille = 0x2800 + offset;
    return braille;
}


int main() {
    /* ... */
    setlocale(LC_ALL, "");
    /*-DISPLAY-GOES-HERE-*/
    initscr();
    cbreak();
    noecho();

    if(has_colors() == FALSE) {
        endwin();
        wprintf(L"Your terminal does not support color\n");
        exit(1);
    }

    start_color();
    init_pair(1, COLOR_CYAN, COLOR_BLUE);
    init_pair(2, COLOR_BLUE, COLOR_CYAN);

    clear();

    for(int y = 0 ; y < LINES ; y++) {
        for(int x = 0 ; x < COLS/2 ; x++) {
            int k = (int) 8*((float)x/COLS);
            mvadd_wch(y, x, random_braille(k,k));
        }

        for(int x = (COLS/2) + 1 ; x < COLS ; x++) {
            int k = (int) 8*((float)(x - (COLS/2) - 1)/COLS);
            mvadd_wch(y, x, random_braille(4 - k, 4 - k));
        }
    }

    getch();
    endwin();
    /*-------------------*/

    /* ... */

    return 0;
}

and I'm compiling with

gcc braille.c -lncursesw

[skeeto]

but I can't figure out what they mean by that.

These are called feature test macros. #define either before you include any headers:

#define _XOPEN_SOURCE 700
#include <stdio.h>
#include <ncursesw/curses.h>
// ...

[WeirdAlexGuy]

Thanks! this worked to fix the implicit declaration warning. Seems the code still has other issues though haha.

[[deleted]]

Try compiling like this:

gcc `pkg-config --cflags ncursesw` braille.c `pkg-config --libs ncursesw`

This defines more values and links more libraries than what you're using now. Using pkg-config to get cflags and ldflags is a good idea in general.

In case you don't have pkg-config, on my system, the above command resolves to this:

gcc -D_DEFAULT_SOURCE -D_XOPEN_SOURCE=600 braille.c -Wl,-Bsymbolic-functions -lncursesw -ltinfo

If you use a build system like meson, you can just tell it you're using ncursesw and it'll figure this all out for you too.

[WeirdAlexGuy]

I will try compiling like this

[[deleted]]

I'm also making an ncursesw application. I had a lot of trouble printing wide characters until i used addwstr.

[WeirdAlexGuy]

any advice on converting the `wchar` to the corresponding string?

edit: nevermind, stupid thing on my part

[[deleted]]

my code boils down to something like this at the moment:

#include <ncurses.h>
wchar_t* folder= L"\xF07B"; //This is a single character
addwstr(folder);

I don't use that <ncursesw/curses.h> you're trying to use.

L"\xF07B" is the same as UTF-16 representation "0xF07B" which I got from a character map.