ncurses get_wch() 函数未声明

Question

我尝试在 Archlinux 安装上检查 ncurses 库中 get_wch 函数的输出。

但是当我调用这个函数时，我得到了这个 GCC 错误：

main.c:6:15: warning: implicit declaration of function "get_wch";

我按照我的 GCC 命令行建议链接了库：

gcc main.c -lncursesw -o exec

我还检查了是否安装了 ncurses：

core/ncurses 6.2-1 [installed]
multilib/lib32-ncurses 6.2-1 [installed]

当我在“usr/include”目录中列出头文件时，我看到在 lib 编译时生成的头文件允许我使用“widec”函数。

#include <curses.h>

int main() {
    initscr();
    int test = 0;
    int result = get_wch(&test);
    printf("Caractère : {} / Function code : {}\n", test, result);
    endwin();
return 0;
}

我不明白如何使用这个库。可用的“文档”似乎对我不利...

Answer 1

gcc 警告

main.c:6:15: warning: implicit declaration of function "get_wch";

告诉你get_wch. X/Open Curses specified all of the wide-character functions conditionally (to avoid breaking old programs). That's summarized in the ncurses manual page没有函数原型：

You must also enable the wide-character features in the header file when compiling for the wide-character library to use the extended (wide-character) functions. The symbol which enables these features has changed since XSI Curses, Issue 4:

Originally, the wide-character feature required the symbol _XOPEN_SOURCE_EXTENDED but that was only valid for XPG4 (1996).

Later, that was deemed conflicting with _XOPEN_SOURCE defined to 500.

As of mid-2018, none of the features in this implementation require a _XOPEN_SOURCE feature greater than 600. However, X/Open Curses, Issue 7 (2009) recommends defining it to 700.

Alternatively, you can enable the feature by defining NCURSES_WIDECHAR with the caveat that some other header file than curses.h may require a specific value for _XOPEN_SOURCE (or a system-specific symbol).

get_wch 的原型使用 wint_t（一个可以容纳“宽字符”的整数，例如 Unicode）。 manual page 列出了宽字符 ncursesw 库（和函数原型）中使用的这些类型：cchar_t , wchar_t 和 wint_t

如果您想使用包含任何这些类型的函数原型，您的程序应该启用该功能。如前所述before，定义NCURSES_WIDECHAR是最简单的。

ncurses get_wch() 函数未声明

ncurses get_wch() function undeclared

c

linux

curses

ncurses

widechar