[英]Why does rl_bind_key with custom function fail in readline on OSX/macOS
我構建了一個外殼,嘗試使用rl_bind_key()
使tab( \\t
)鍵做一些自定義操作,但在macOS Sierra中不起作用,但在Ubuntu,Fedora和CentOS上有效。 這是mcve:
#include <stdlib.h>
#include <stdio.h>
#include <readline/readline.h>
static int cmd_complete(int count, int key)
{
printf("\nCustom tab action goes here...\n");
rl_forced_update_display();
return 0;
}
char *interactive_input()
{
char *buffer = readline(" > ");
return buffer;
}
int main(int argc, char **argv)
{
rl_bind_key('\t', cmd_complete); // this doesn't seem to work in macOS
char *buffer = 0;
while (!buffer || strncmp(buffer, "exit", 4)) {
if (buffer) { free(buffer); buffer=0; }
// get command
buffer = interactive_input();
printf("awesome command: %s\n", buffer);
}
free(buffer);
return 0;
}
我像這樣使用Clang進行編譯:
$ cc -lreadline cli.c -o cli
造成這種現象的原因是什么,我該如何解決?
我使用的是-lreadline
標志,但是我不知道,Clang似乎在秘密使用libedit(我也看到過它也稱為editline)。 在libedit中,由於某種原因(這會帶來另一個問題), rl_bind_key
似乎不適用於rl_insert
以外的任何東西。
因此,我找到的一種解決方案是使用Homebrew安裝GNU Readline( brew install readline
),然后確保使用該版本,因此進行編譯:
$ cc -lreadline cli.c -o cli -L/usr/local/opt/readline/lib -I/usr/local/opt/readline/include
實際上,當您安裝readline時,它將在安裝結束時告訴您此信息,或者您是否進行brew info readline
:
gns-mac1:~ gns$ brew info readline
readline: stable 7.0.3 (bottled) [keg-only]
Library for command-line editing
https://tiswww.case.edu/php/chet/readline/rltop.html
/usr/local/Cellar/readline/7.0.3_1 (46 files, 1.5MB)
Poured from bottle on 2017-10-24 at 12:21:35
From: https://github.com/Homebrew/homebrew-core/blob/master/Formula/readline.rb
==> Caveats
This formula is keg-only, which means it was not symlinked into /usr/local,
because macOS provides the BSD libedit library, which shadows libreadline.
In order to prevent conflicts when programs look for libreadline we are
defaulting this GNU Readline installation to keg-only..
For compilers to find this software you may need to set:
LDFLAGS: -L/usr/local/opt/readline/lib
CPPFLAGS: -I/usr/local/opt/readline/include
所以這就是為什么它在libedit中不起作用的原因。 我下載了源代碼,這是rl_bind_key
函數的定義方式:
/*
* bind key c to readline-type function func
*/
int
rl_bind_key(int c, rl_command_func_t *func)
{
int retval = -1;
if (h == NULL || e == NULL)
rl_initialize();
if (func == rl_insert) {
/* XXX notice there is no range checking of ``c'' */
e->el_map.key[c] = ED_INSERT;
retval = 0;
}
return retval;
}
因此,似乎設計為除rl_insert
之外rl_insert
不能使用。 這似乎是一個錯誤,而不是功能。 我希望我知道如何成為libedit的貢獻者。
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