"curs_set()" 未能 return 先前的游标状态

Question

根据 curs_set 手册页：

The curs_set routine sets the cursor state to invisible, normal, or very visible for visibility equal to 0, 1, or 2 respectively. If the terminal supports the visibility requested, the previous cursor state is returned; otherwise, ERR is returned.

但是下面的简单程序并没有return之前的状态：

[STEP 107] # cat curs_set.c
#include <stdio.h>
#include <curses.h>

int main()
{
    int ret;

    initscr();
    ret = curs_set(1);
    endwin();

    printf("curs_set() returned %d\n", ret);

    return 0;
}
[STEP 108] # gcc curs_set.c -lncurses
[STEP 109] # setterm -cursor off
[STEP 110] # ./a.out             <-- cursor invisible
curs_set() returned 1            <-- why not 0?
[STEP 111] # tput civis          <-- cursor visible
[STEP 112] # ./a.out             <-- cursor invisible
curs_set() returned 1            <-- why not 0?
[STEP 113] #                     <-- cursor visible

我是不是漏掉了什么？

Answer 1

正如评论中 @vonaka 所提醒的那样，手册页还说（在单独的 NOTES 部分）：

Both ncurses and SVr4 will call curs_set() in endwin() if curs_set() has been called to make the cursor other than normal, i.e., either invisible or very visible. There is no way for ncurses to determine the initial cursor state to restore that.

"curs_set()" 未能 return 先前的游标状态

"curs_set()" failed to return the previous cursor state

c

ncurses

tty