C语言 libreadline编辑和执行命令支持

Question

在bash(和其他)中，我可以使用C-x C-d或其他键绑定来编辑命令，使用在$EDITOR或$VISUAL中定义的外部编辑器。

但是，当我在程序中使用libreadline时，默认情况下它没有类似的功能。

如何在程序中启用它?或者这是bash特有的特性，而不是libreadline?那么如何实施呢?

Answer 1

刚刚看了一下Bash源代码中的bashline.c，发现:

1 /* bashline.c -- Bash's interface to the readline library. */
...
440 /* Called once from parse.y if we are going to use readline. */
441 void
442 initialize_readline ()
443 {
...
482   rl_add_defun ("edit-and-execute-command", emacs_edit_and_execute_command, -1);
...
592   /* Bind C-xC-e to invoke emacs and run result as commands. */
593   rl_bind_key_if_unbound_in_map (CTRL ('E'), emacs_edit_and_execute_command, emacs_ctlx_keymap);
594 #if defined (VI_MODE)
595   rl_bind_key_if_unbound_in_map ('v', vi_edit_and_execute_command, vi_movement_keymap);
...
924 #define VI_EDIT_COMMAND         "fc -e "${VISUAL:-${EDITOR:-vi}}""
925 #define EMACS_EDIT_COMMAND      "fc -e "${VISUAL:-${EDITOR:-emacs}}""
926 #define POSIX_VI_EDIT_COMMAND   "fc -e vi"
...
1003 #if defined (VI_MODE)
1004 static int
1005 vi_edit_and_execute_command (count, c)
1006      int count, c;
1007 {
1008   if (posixly_correct)
1009     return (edit_and_execute_command (count, c, VI_EDITING_MODE, POSIX_VI_EDIT_COMMAND));
1010   else
1011     return (edit_and_execute_command (count, c, VI_EDITING_MODE, VI_EDIT_COMMAND));
1012 }
1013 #endif /* VI_MODE */
1014 
1015 static int
1016 emacs_edit_and_execute_command (count, c)
1017      int count, c;
1018 {
1019   return (edit_and_execute_command (count, c, EMACS_EDITING_MODE, EMACS_EDIT_COMMAND));
1020 }
....