Using icons in X11 c++ app

[Foroughi]

Hi there.
It's been a while since I'm trying to use this icon pack header in my X11 window manager (written in c++) but I couldn't.
I hope you can help me with that.
So here is what I have done :

1 - Downloaded the c++ header file. As I noticed in each header file it has been mentioned what font I should use. So I downloaded the fonts accordingly. put them in .font folder and fc-cache -rv

2 - then I tried to use the following code to show an icon but what I get is an empty rectangle. (I tried to simplify it as much as i could but you can find the link of repo at the end)

#define ICON_FONT "Font Awesome 6 Free-7" 

//also tested with "FontAwesome-7" 
//also tested with "fontawesome-7" 

auto d = XftDrawCreate(this->CurrentDisplay, this->root, DefaultVisual(this->CurrentDisplay, DefaultScreen(this->CurrentDisplay)), DefaultColormap(this->CurrentDisplay, DefaultScreen(this->CurrentDisplay)));
auto iconfont = XftFontOpenName(this->CurrentDisplay, DefaultScreen(this->CurrentDisplay), ICON_FONT);
XftDrawString8(d, &selectedcolor, iconfont, 10 ,  10 ,  (FcChar8 *)ICON_MAX_FA, 1);

Btw that code is working when I want simply to draw a text.
Also here is the whole repo in case you want to check

[dougbinks]

Note that ICON_MAX_FA is not a UTF8 string, it is an integer value for the largest icon. If you want to test drawing an icon you should use one such as ICON_FA_ADDRESS_BOOK.

We don't have any experience with using these fonts directly with Xft, however if the above does not work I would first check that XftFontOpenName is loading the font correctly. I note from this xft-example code that the fontname might also need to specify size.

[Foroughi]

Sadly using ICON_FA_ADDRESS_BOOK didn't help. I also changed the font name and it didn't help. I am gonna check the example you sent.
Let me know if you found any examples.
thanks for the help anyway.

[Foroughi]

In case anyone else went through the same problem, please include the font style if you want to use font awesome. So in this case I used Font Awesome 6 Free:size=14:style=Solid and it worked like a charm.