在emacs编程中有以下需求
- 从调用一个函数的地方跳转到函数的定义的地方
- 或是反过来从函数定义的地方列出所有调用这个函数的地方
实现办法
需要安装以下软件
- gnu global（阅读源代码的工具）官网
- emacs的gtags插件
- 启动emacs后，输入下面的命令，来启动gtags的功能
M-x ggtags-mode
gnu global安装
apt-get install global
emacs的gtags插件安装
M-x list-packages
找到ggtags后，鼠标点击，再点安装
使用方法
1，在存放代码的根目录执行：
$ gtags
执行后，会发现在生成了3个文件， GPATH GRTAGS GTAGS
2，启动emacs
3，启动emacs后，输入下面的命令，来启动gtags的功能
M-x ggtags-mode
每打开一个文件都输入ggtags-mode，太麻烦了，所以在.emacs文件里加一个钩子，当打开c,c++,java的源文件时，自动启动ggtags-mode
(add-hook 'c-mode-common-hook
(lambda ()
(when (derived-mode-p 'c-mode 'c++-mode 'java-mode)
(ggtags-mode 1))))
4，使用下面的函数就可以实现，查看代码的各种需求了。
ggtags-find-tag-dwim
Find a tag by context.
If point is at a definition tag, find references, and vice versa.
If point is at a line that matches ``ggtags-include-pattern``, find
the include file instead.
To force finding a definition tag, call it with a prefix (``C-u``).
ggtags-find-tag-mouse
Like ``ggtags-find-tag-dwim`` but suitable for binding to mouse
events.
ggtags-find-definition
Find definition tags. With ``C-u`` ask for the tag name with
completion.
ggtags-find-reference
Find reference tags. With ``C-u`` ask for the tag name with completion.
ggtags-find-other-symbol
Find tags that have no definitions. With ``C-u`` ask for the tag
name with completion.
ggtags-find-tag-regexp
Find definition tags matching a regexp. By default it lists all
matching tags in the project. With ``C-u`` restrict the lists to a
directory of choice.
ggtags-idutils-query
Use idutils to find matches.
ggtags-grep
Grep for lines matching a regexp. This is usually the slowest.
ggtags-find-file
Find a file from all the files indexed by ``gtags``.
ggtags-query-replace
Do a query replace in all files found in a search.
Handling multiple matches
+++++++++++++++++++++++++
When a search finds multiple matches, a buffer named
``*ggtags-global*`` is popped up and ``ggtags-navigation-mode`` is
turned on to facilitate locating the right match.
``ggtags-navigation-mode`` makes a few commands in the
``*ggtags-global*`` buffer globally accessible:
``M-n``
Move to the next match.
``M-p``
Move to the previous match.
``M-}``
Move to next file.
``M-{``
Move to previous file.
``M-=``
Move to the file where navigation session starts.
``M-<``
Move to the first match.
``M->``
Move to the last match.
``C-M-s`` or ``M-s s``
Use ``isearch`` to find the match.
``RET``
Found the right match so exit navigation mode. Resumable by ``M-,``
(``tags-loop-continue``).
``M-*``
Abort and go back to the location where the search was started.
Miscellaneous commands
++++++++++++++++++++++
Commands are available from the ``Ggtags`` menu in ``ggtags-mode``.
ggtags-prev-mark
Move to the previously (older) visited location. Unlike ``M-*``
this doesn't delete the location from the tag ring.
ggtags-next-mark
Move to the next (newer) visited location.
ggtags-view-tag-history
Pop to a buffer listing all visited locations from newest to
oldest. The buffer is a next error buffer and works with standard
commands ``next-error`` and ``previous-error``. In addition ``TAB``
and ``S-TAB`` move to next/prev entry, and ``RET`` visits the
location. ``M-n`` and ``M-p`` move to and display the next/previous
entry.
ggtags-view-search-history
View or re-run past searches as kept in
``ggtags-global-search-history``.
ggtags-kill-file-buffers
Kill all file-visiting buffers of current project.
ggtags-toggle-project-read-only
Toggle opening files in ``read-only`` mode. Handy if the main
purpose of source navigation is to read code.
ggtags-visit-project-root
Open the project root directory in ``dired``.
ggtags-delete-tags
Delete the GTAGS, GRTAGS, GPATH and ID files of current project.
ggtags-explain-tags
Explain how each file is indexed in current project.
ggtags-browse-file-as-hypertext
Use ``htags`` to generate HTML of the source tree. This allows
browsing the project in a browser with cross-references.
使用举例
1，从调用一个函数的地方跳转到函数的定义的地方
M-x ggtags-find-definition
对应的快捷键：M-.
2，从调用一个函数的地方跳转到函数的定义的地方后，返回到调用函数的地方
M-x ggtags-prev-mark
对应的快捷键：M-,
3，或是反过来从函数定义的地方列出所有调用这个函数的地方
M-x ggtags-find-reference
对应的快捷键：M-]
4，查看导航过的历史记录
M-x ggtags-view-tag-history
对应的快捷键：C-c M-h