Open cscope results in the same buffer - emacs

This might seem to be a very very stupid question.
But for the past few years I have been using vim and cscope on the terminal, with some screen to make life a bit bearable.
I have just started to learn emacs and it is much more satisfying to use it.
Problem using emacs:
Every time I do M-x find-c-symbol, I get a new buffer with a bunch of files, but I don't know how to open the file at the exact line number.
I googled a lot and found this to open file under cursor: M-x ffap
but this opens at the first line. Can some emacs expert help me??
Thanks

I've got both Emacs 23.x and 24.x installed, both setup with working cscope and xcscope installs. Neither has a "find-c-symbol" function, but there is a "cscope-find-this-symbol", which is what I assume you're actually using.
I'm going to assume you're using a GUI version, and not the text-only version, and that you're actually getting the *cscope* buffer automatically being opened and created (since that's what it sounds like from your description).
For a simple search, I'll get results that look like this:
Finding symbol: debug
Database directory: /home/user/emacs_tags/modular/
-------------------------------------------------------------------------------
*** /home/user/code/modular/frontend/common/controller.test/src/MainTest.cpp:
<global>[73] #ifdef debug
-------------------------------------------------------------------------------
Database directory: /home/user/emacs_tags/rrsdk/
-------------------------------------------------------------------------------
*** /home/user/code/rrsdk/fs/apps/busybox/src/shell/ash.c:
<global>[303] #define debug optlist[15 + ENABLE_ASH_BASH_COMPAT]
*** /home/user/code/rrsdk/bootloader/u-boot/src/board/mcc200/auto_update.c:
<global>[53] #undef debug
<global>[55] #define debug(fmt,args...) printf (fmt ,##args)
<global>[57] #define debug(fmt,args...)
-------------------------------------------------------------------------------
Search complete. Search time = 22.44 seconds.
Assuming your results look similar (they should), there are two multiple target areas in the result. Each file line (the lines starting with ***) is a target to the start of that file. Each individual result is also a target area. If you click on one of the lines that lists a specific match (or put your cursor on it and press enter), it will attempt to jump to the specific line matching the result. If it's not jumping to the specific line correctly it usually means your code has changed since the last time the cscope index file was generated.
I'm not sure how you're using the cscope tool, but you can setup xcscope to auto-index on every change to keep the file up to date, but it really only works for smaller code bases where you can keep the cscope.out files in the top level directory and provide it with a full file list for the files to index. Most people I've talked to use the cscope tool by hand in an external script to manually index/re-index every once in a while and then just interface to the existing cscope database(s) using the emacs tools (mine takes about 4 hours to generate the cscope database for a project that includes the Linux kernel as a sub-part).

Related

Emacs - How do I get projectile to open file in current window?

I've spent a whole day on this now. Say I open emacs and press C-c p p to open projectile-switch-project then RET to select a project, emacs opens a new window horizontally (on top of the previous) with the current buffer.
What I need is for projectile to use the already existing window and not open a new one. I've gone through every single line of my config and can figure out what is causing it.
I'd have posted my config but it's split over multiple files which will make it impractical to link to here.
The related packages I can think of which I use are:
projectile,
ivy swiper counsel - trilogy
What I've tried so far is start emacs without loading (ivy swiper counsel) and also I've tried replacing all my projectile code with bare minimum:
(use-package projectile
:ensure t
:init
(projectile-mode +1)
:bind (:map projectile-mode-map
("s-p" . projectile-command-map)
("C-c p" . projectile-command-map)))
which didn't work either.
I'm not expecting any specifics since it's a hand crafted config however I'm hoping for general pointes as to where to look for the possible cause.
I'm researching more to see if i can find a better way for you, but this is what i have so far...
If you want to look around the customization options just type M-x customize. I found a ton of options you can browse through. Projectile was listed under "Convenience" and frames/windows were listed under "Environment". You can also search packages you might be interested in for more customization if you have MELPA installed.
Considering the way that buffers and windows work I don't think you can just replace the content inside the buffer with the content of another file. I think (or at least how I've been using Emacs) you will always open a new buffer to open a file and close old buffers if needed.
From what I was reading, buffers are like interfaces between Emacs and the file you're peering into. It sets up a connection, points to the file, and creates a name for the buffer (usually from the file name unless you change it). Something I find interesting is you can even have multiple buffers open to the same file and as you type on the screen in one buffer the text should show up in the other buffer in real time.
I was reading some documentation on it and I think the command you're looking for is C-x C-f or C-x d, which opens DiredMode. The first one opens your home directory and the second opens the current directory for the file in your selected buffer. This will open a mini-buffer to search through files and when you choose the file it should open the file in a new buffer on top of the buffer you were looking at initially.
Then you can use C-x b to list and move between other buffers that are already open.
Also, M-x projectile-find-file is a command you can use to search files and get the same outcome. I don't have that set to a key-binding so I don't know if there is a default, plus I'm using Spacemacs with evil-mode, so not everything is the same as original Emacs.
Also, maybe look into extension you can get from MELPA like Treemacs

reduce load time emacs [duplicate]

I use Emacs v. 22 (the console version, either remotely with PuTTY or locally with Konsole) as my primary text editor on Linux. It takes a while to load up each time I start it though, probably almost a second, although I never timed it. I tend to open and close Emacs a lot, because I'm more comfortable using the Bash command-line for file/directory manipulation and compiling.
How can I speed up the start-up time?
Others have covered using gnuserve and emacsclient, and I'd suggest compiling within emacs (being able to jump to compilation errors is a win).
But, specifically speeding up the .emacs can be done by:
Byte compiling the .emacs file, which you can do automatically by using this snippet of code
Replacing as many of the (require 'package) statements with autoloaded functionality. This will delay loading of lisp until it's actually required. Using this technique allowed me to speed up my startup from >6 seconds to <1. This takes a little bit of work because not all libraries come properly marked autoload.
Removing code/functionality you no longer use.
Try running emacs with the option --no-site-file to avoid loading unnecessary packages in the site installation site-start.el.
If you are really serious, you can roll your own emacs with your favorite functionality already loaded. This, of course, means it's more involved to make changes to what you have in your .emacs because it's a part of the binary. Follow the link for information on how to use dump-emacs.
Buy a faster computer and/or faster disk.
How to determine what your .emacs loads
Now, how do you find out what your .emacs loads? With the goal to remove the functionality, or to delay it? Check your *Messages* buffer, which contains lines like:
Loading /home/tjackson/.emacs.tjackson.el (source)...
Loading /home/tjackson/installed/emacs/lisp/loaddefs.el (source)...done
Loading /user/tjackson/.elisp/source/loaddefs.el (source)...done
Loading autorevert...done
Loading /home/tjackson/.emacs.tjackson.el (source)...done
If you'll notice, the Loading statements can nest: the first .emacs.tjackson.el ends with ... and the last line shows the .emacs.tjackson.el load is ...done. All those other files are loaded from inside my .emacs.tjackson.el file. All the other loads are atomic.
Note: If you have a large .emacs, it's possible that the *Messages* buffer will lose some of the messages because it only keeps a fixed amount of information. You can add this setting early on to your .emacs to keep all the messages around:
(setq message-log-max t)
Note: It the 'load command will suppress the messages if its fourth argument nomessage is non-nil, so remove any such invocations (or, advise 'load and force the fourth argument to be nil).
In addition to Adam Rosenfield's solution, I recommend to use Emacs in server mode. You may add (server-start) to your dotemacs, and run emacsclient instead of emacs whenever you want to open file in Emacs. That way you have to pay the loading cost of Emacs only once, after then clients pop up immediately.
Edit
You're right, v22 does not create a new frame. Create a shell script that do the trick:
#!/bin/bash
# Argument: filename to open in new Emacs frame
/usr/bin/emacsclient -e '(let ((default-directory "`pwd`/")) (select-frame (make-frame)) (find-file "'$1'"))'
Edit 2
In v24+, you can do emacsclient -c to create a new frame.
Don't close Emacs every time you want to use the shell. Use Ctrl-Z to move Emacs to the background and the fg command in Bash to move it back to the foreground.
A couple of tips:
Use autoloads
Using autoload saves you from loading libraries until you use them.
For example:
(if (locate-library "ediff-trees")
(autoload 'ediff-trees "ediff-trees" "Start an tree ediff" t))
Compile your .emacs
Gives you a slight speed increase although there are pitfalls if you
work with version control and your .emacs is newer than .emacs.elc.
One common trick is:
(defun autocompile nil
"compile itself if ~/.emacs"
(interactive)
(require 'bytecomp)
(let ((dotemacs (file-truename user-init-file)))
(if (string= (buffer-file-name) (file-chase-links dotemacs))
(byte-compile-file dotemacs))))
(add-hook 'after-save-hook 'autocompile)
Learn to love emacs server.
Running emacs as a server means never having to close it down. However
I note your still using emacs22. emacs23 supports multi-tty which makes
it a lot easier to run emacs in one screen session and then bring up
new windows in another terminal. I use emacs to edit mail for my mail
client (mutt) and emacsclient is fantastic for these sort of quick edits.
One of
M-x shell
M-x eshell
M-x term
M-x ansi-term
should meet your command-line needs from within Emacs.
You can also use M-! (aka M-x shell-command) to execute a one-liner without dropping to the shell.
Check your .emacs file to see if you're loading unnecessary packages. Loading packages can take a significant amount of time. For example, you might only want to load the php-mode package if you're editing a PHP file. You can do that by installing a hook procedure, although I'm not certain of the details.
Also make sure that any packages you're loading are compiled (.elc files). You can compile an elisp file by running
emacs -batch -f batch-byte-compile thefile.el
Compiled packages load much faster than uncompiled packages.
"I tend to open and close emacs a lot, because I'm more comfortable using the bash command line for file/directory manipulation and compiling."
You're describing the way an editor like vim is used like. Shoot in&out. Emacs is usually kept open, and mostly all is done from "within it". hiena already answered what would be the correct approach here.
The fastest way is to profile your .emacs. I cut down my load time from >3s to 1s in 5 minutes after I found that 4 particular lines in my .emacs were taking up more than 80% of the load time.
One thing that helped me reduce the load time of my .emacs, in addition to autoload (as others have suggested), is eval-after-load. In the following example, delaying the call to sql-set-product saves you from having to load sql in your .emacs, making the exisiting sql autoloads more effective.
(eval-after-load "sql"
'(progn
(sql-set-product 'mysql)
(setq sql-mysql-options '("-C" "-t" "-f" "-n"))
(setq sql-sqlite-program "sqlite3")
))
Of course, for some packages there will be a hook available that you can do the same thing, but sometimes there isn't, or else this way just proves easier to think about.
Emacs is designed to run "all the time" (or at least for long periods of time), thus starting and stopping Emacs several times during a day is not recommended.
I would suggest using screen. Screen is a terminal multiplexer, giving you an unlimited virtual terminals in one terminal.
After installing simply write "screen emacs" in your terminal. Emacs will start as usual, but pressing "c-a c" (that is press ctrl-a and then c) will open a new virtual terminal. You can get back to emacs by pressing "c-a c-a" (that's two times ctrl-a).
You can even detach from the running screen session, the key sequence is "c-a d".
Re-attach to the session by issuing "screen -R" and you will be back where you left. This enables you to start an emacs session at work, detach, go home, and re-attach from home.
I've been running Emacs like this for months in a row.
Here's the official web site: http://www.gnu.org/software/screen/ but try googling for screen tutorials and howtos
You can use benchmark-init to profile your Emacs startup. It will keep track of what modules are being loaded and how much time is spent on each. The results can be presented either in a tabulated form or as a tree. The tree makes it easier to track who loads what, which can be helpful when you load a package with a lot of dependencies, and the tabulated form helps you quickly find where most of the time is being spent.
Once you have these results try to figure out if all of the modules have to be loaded all the time or if you can perhaps load some of them on-demand. For instance, in my configuration I only load Emacs extensions that are specific to certain modes when that mode is actually activated since most of the time I only use a small subset of them in a session. eval-after-load and mode hooks will be your friends here.
By applying this method my Emacs starts in 3-4 seconds and I have close to 200 extensions installed. Most of the time is spent loading Helm, which I always load since it replaces find-file and other core functions that are always needed, and CEDET, since I use the latest version and it has to be loaded before Emacs tries to load the older built-in version.
Try using the https://github.com/jwiegley/use-package macro to define your package loads and customizations. It handles deferred loading of packages for you, making it relatively easy to get good startup times even in the presence of large numbers of configured packages. I have almost 100 packages referenced in my .emacs, but my startup time is under 2 seconds on Linux, and 2.2s on the Mac.
One thing that others haven't mentioned is to include the elisp libraries you use as part of the dumped Emacs to move the library loading time from Emacs startup to Emacs build. It is not for the faint-hearted, but if you load several libraries in .emacs it could win you a few seconds of startup time.
I had around 120sec start time. I was able to find the fix installing this:
https://github.com/dholm/benchmark-init-el
put on top of your init.el
(let ((benchmark-init.el "~/.emacs.d/el-get/benchmark-init/benchmark-init.el"))
(when (file-exists-p benchmark-init.el)
(load benchmark-init.el)))
then once your emacs started, run:
M-x benchmark-init/show-durations-tree
On my side the problem was 127 secs in tramp-loaddefs
I fixed it by adding
127.0.0.1 host.does.not.exist
to /etc/hosts and that made my startup fast
see more here: https://github.com/emacs-helm/helm/issues/1045
another thing that maybe helpful to you: https://www.emacswiki.org/emacs/ProfileDotEmacs
This doesn't answer the question, but is kind of relevant
I don't know how to make it start faster, but there are a few things I could suggest:
for most things you do on the command line, you can do them in emacs:
compile: M-x compile, then type the command you use
my experience is only with C++, but with g++ you can press C-x ` to jump to lines that the compiler complains about
run shell commands: M-!, dumps output into a buffer
interactive shell: M-x shell
alternatively, you could run emacs like this:
emacs file.ext &
which opens emacs in the background so you can still use the shell ( this works best with putty and X forwarding with something like Xming)
I was trying to solve the same problem, when I came across this question here. I just wanted to add that the problem for me was not because of the load time of emacs lisp packages, but the fact that the host did not have a fully resolved hostname
To check your package load time do
M-x emacs-init-time
For me it was 0.3 seconds, and yet the load time was extremely high.
After changing my hostname correctly, it fixed the problem.
To configure your fully resolved hostname edit /etc/hostname, and /etc/hostsfile with:
127.0.0.1 localhost localhost.localdomain
192.168.0.2 hostname hostname.domain
I would have to check my customization, but there is a package called gnuserve or emacsclient. It migrates a lot so you will have to google for it.
It runs one emacs session in the background. Any further sessions of emacs are essentially just new frames of that session. One advatage is quick startup times for your later sessions.

Emacs command to Find and Open File similar to Eclipse

I've recently switched from using Eclipse to emacs. I'm trying to find a way to emulate eclipse's Ctrl-Shft-r functionality which lets you type in a file name and it begins showing all files in the current workspace that begin with the string you are typing.
C-x C-f seems to handle just tab-completion in the current directory, whereas Eclipse's functionality looked through all sub-directories to find matching files.
I'm looking for something (maybe there's a plugin that does this) that allows you to type the name of folder to look in, and then a partial file and returns back the results in a buffer. Possibly that uses auto-complete to list off matching files with their full paths.
First of all, steer clear of vanilla find-file function (that's the interactive function that is run when you hit C-x C-f). It is very limited, it forces you to hit TAB all the time, and the first thing most people do when switching to emacs is replace find-file with something more powefull.
There're a number of alternatives. ido-mode is one, helm is another. The former is light-weight, fast and comes built-in with emacs. The latter is immensely powerful and strives to be fast, too.
Second of all, there're two ways a recursive file search can usually be done:
directory search - that's when you just search a directory, no surprises here;
project search - that's when you setup a project your're working on, thus making emacs aware of which files are of interest to you right now.
For directory search, ido-find-file and helm-find-file are both viable options. Ido does its search automatically when you pause typing; helm uses (C-u) M-g s to activate grep. See this SO question for more info.
For project search, you need a library to manage your projects. Projectile is great for that. Set it up and use C-c p f or C-c p F to list files in current or all of your projects, respectively. Oh, and projectile uses ido by default, but there is helm support, too.
You're looking for projectile which indexes your project's files. I used it for a while but have recently switched to using helm-recentf
(global-set-key "\C-x\ \C-r" 'helm-recentf)
I have recent files set to a large number. Pretty much anything I've ever opened is a few keystrokes away. This even doubles up as a handy way to switch buffers.
(require 'recentf)
(setq recentf-auto-cleanup 'never)
(recentf-mode 1)
(setq recentf-max-saved-items 200)

How to have find-file's prompt match Emacs shell's $PWD?

With Emacs, if the current buffer is one that's "visiting" a normal file (for example), whose full pathname is /path/to/somefile, and one runs find-file (C-x C-f), the prompt that appears in the mini-buffer is something like
Find file: /path/to/▮
...with the cursor placed as indicated above by ▮. IOW, the suggested path shown by default is always to the directory containing the file that the current buffer is visiting.
If, however, the current buffer is an Emacs shell process, and one runs find-file, then, AFAICT, the path shown in the prompt remains fixed at the value of $PWD when the shell process was started, irrespective of the current value of $PWD:
Find file: /pwd/at/startup/▮
This behavior is not so useful, because the $PWD at startup often becomes irrelevant later on. It would be really nice if the directory shown in find-file's prompt were instead the shell process's current $PWD.
Is there a simple way to modify find-file to behave this way whenever the current buffer is a shell process?
You want "shell directory tracking". E.g. check dirtrack-mode or shell-dirtrack-mode.
shell-dirtrack-mode tries to parse "cd" commands, (event_jr: which in my experience does not work consistently). dirtrack-mode uses the prompt regexp, which works very well.
There are a number of ways to manage this. As Stefan notes, there are a couple of built in packages that manage it.
My preferred way is to alter your prompt (when in Emacs) to have the $PWD embedded in it, and then Emacs strips it out and uses it. This has the benefit of always being up to date. I've found that dirtrack-mode sometimes gets out of sync.
Check out my solution here, which is a modification of a similar implementation on the Emacs Wiki.

What is the correct path to the C source files for Emacs?

So, way back in January, I went here:
http://emacsformacosx.com/
I downloaded Emacs and have been using it on my Mac and I like it. I've started trying to get into Elisp programming. To learn more, I'd like to look up some functions. So for instance I do:
C-h f
and then type "scroll-down"
This gives me the following text:
>scroll-down is an interactive built-in function in `window.c'.
>
>It is bound to <kp-prior>, <prior>, C-1, C-x C-1, M-v.
>
>(scroll-down &optional ARG)
>
>Scroll text of selected window down ARG lines.
>If ARG is omitted or nil, scroll down by a near full screen.
>A near full screen is `next-screen-context-lines' less than a full screen.
>Negative ARG means scroll upward.
>If ARG is the atom `-', scroll upward by nearly full screen.
>When calling from a program, supply as argument a number, nil, or `-'.
And the text "window.c" is a link. So I click on the link and I get:
find-function-C-source: The C source file window.c is not available
I'm getting this error a lot while doing a lot of different things. Where do I find the right path, and how do I tell Emacs what that path is?
I did just recently install some ELPA packages, so maybe one of them is causing some chaos?
The variable source-directory will point to the location where the C sources are. If you have a separately downloaded copy, you'll have to point this variable to that directory.
Most packagers don't include the sources, or split them off into a separate package. Install the sources (and maybe tweak an init script to tell Emacs where you put them, if it's not the default location. The pertinent variable is find-function-C-source-directory).
If you didn't manually build Emacs from the source code and patch the C source code, value of source-directory or find-function-C-source-directory would be wrong.
You can manually download Emacs source code, unpack it somewhere and set above two variables accordingly like following
(setq source-directory "/path/to/your-emacs-repo")
;; OR
(setq find-function-C-source-directory "/path/to/your-emacs-repo/src")
GNU Emacs source code and development is hosted on savannah.gnu.org. You can find all the tags here and download the one that matches your M-x emacs-version.