如何在 Rust 中顯示帶有 ncurses 的字符？

Question

我試圖通過簡單地在終端中添加一個字符

use ncurses::*;
fn main()
{
    initscr();
    addch('#');
    endwin();
}

但我收到以下錯誤：

error[E0308]: mismatched types
  --> src/main.rs:15:11
   |
15 |     addch('#');
   |           ^^^ expected `u32`, found `char`

我檢查了文檔，它說它需要一個chtype ，所以我認為這只是一個字符？ 我不確定我應該如何將字符更改為u32 。 char和chtype有什么區別？

Answer 1

通過查看定義為u64 （對於 64 位平台）和u32 （對於 32 位平台）的別名的源代碼chtype 。

#[cfg(feature="wide_chtype")]
pub type chtype = u64;
#[cfg(not(feature="wide_chtype"))]
pub type chtype = u32;

為了解決這個錯誤，你可以輸入 cast # to chtype 。

fn main()
{
    initscr();
    addch('#' as chtype);
    endwin();
}

Answer 2

chtype包含多個字符，如 ncurses手冊頁中所述：

      ncurses
           the "normal" library,  which  handles  8-bit  characters.   The
           normal   (8-bit)   library   stores  characters  combined  with
           attributes in chtype data.

           Attributes alone (no corresponding character) may be stored  in
           chtype or the equivalent attr_t data.  In either case, the data
           is stored in something like an integer.

有關更多信息， waddch手冊頁詳細說明：

   Video attributes can be combined with a character  argument  passed  to
   addch  or  related  functions by logical-ORing them into the character.
   (Thus, text, including attributes, can be  copied  from  one  place  to
   another  using  inch(3x)  and  addch.)   See the curs_attr(3x) page for
   values of predefined video attribute constants  that  can  be  usefully
   OR'ed into characters.