This question may be a little off topic. But I was wondering if there was a way for me to look at the descriptions of C functions using vim or neovim. Is it possible to look at their documentations by doing something like :help? This would really be helpful since I wouldn't need to lookup to my browser everytime.
I am unclear about these things:
Can :help be my friend here ?
Can I use LSPs to do something like this ?
I am using latest Neovim inside Ubunutu 20.04 in WSL. Is this helpful somehow ?
By pressing K, the keyword under the cursor is looked up using a configured keyword lookup program, the default being man. This works pretty much out of the box for the C standard library.
For C++, you might want to look at something like cppman.
Well yes, you can get the description of C functions by using a LSP (language server plugin)! Here is an image of me using clangd as my LSP:
You'd "just" need to install the LSP and start it. I don't know how familiar you're with neovim, but just in case if you don't know how to install a plugin or to be more specifique: If you don't know how you can install a LSP server, then you can do the following:
There're plenty videos how to set up a LSP-Server for your language. Here's an example.
If you don't want to set up on your own, you can pick up one of the preconfigured neovim setups (some of my friends are recommending lunarvim)
But yeah, that's it. If you have any further questions feel free to ask them in the comments.
Happy vimming c(^-^)c
Let's explain how "K" command works in more detail.
You can run external commands by prefixing them with :! command. So running man tool is as easy as
:!man <C-R><C-W>
Here <C-R><C-W> is a special key combination used to put word under cursor from text buffer down to command line.
Same for showing Vim's built-in help page
:help <C-R><C-W>
As it feels tedious to type that, Vim also defines K Normal mode command that does pretty much the same thing. Except the tool name is taken from value of an option named "keywordprg".
So doing set keywordprg=man (default for *nix systems) makes K to invoke !man tool; while set keywordprg=:help is for bultin help.
Also, the option :h 'keywordprg' is made global or local-to-buffer, so any Vim buffer is able to overwrite global setting. For example, this is already done by standard runtime for "vim" and "help" buffers, so they call ":help" instead of "man".
The problem with :!man command is that it shows "black console". It'd be nice if we could capture man's output and open it inside Vim just like a builtin help page. Then we could also apply some pretty highlighting, assign key macros and all such. This is a pretty common trick and it is already done by a standard plugin shipped with Vim/Neovim.
A command that the plugin provides is called :Man, so you can open :Man man instead of :!man man, for example. The plugin is preactivated in Neovim; for Vim you still need to source one file manually. So to make use of this plugin you'll need something like this
set keywordprg=:Man
if !has("nvim")
source $VIMRUNTIME/ftplugin/man.vim
endif
The previous answer recommending cppman is the way to go. There is no need to install a bulky language server just for the purpose of having the hover functionality. However, make sure you're caching the man pages via cppman -c. Otherwise, there will be a noticeable delay since cppman is fetching the page from cppreference.com on the fly.
If you like popups for displaying documentation, convert the uncompressed man pages (groff -t -e -mandoc -Tascii <man-page> | col -bx), and set keywordprg to your own wrapper to search for keywords according to your needs.
Related
I want to know how can I easily click (or maybe use some easy shortcuts) on a function name and find all its callee or open where it has been defined. Most of the web manuals in web are really hard to follow or don't happen to work out. Say I want to click on allocuvm and see where it has been defined?
uint newstk=allocuvm(pgdir, USERTOP-PGSIZE, USERTOP);
cscope minimal example
Ingo mentioned it, here is an example.
First you should set on your .vimrc:
set cscopequickfix=s-,c-,d-,i-,t-,e-
Then to the base directory of your project and run:
cscope -Rb
This generates a cscope.out file which contains the parsed information. Generation is reasonably fast, even for huge projects like the Linux kernel.
Open vim and run:
:cs add cscope.out
:cs find c my_func
c is a mnemonic for callers. The other cscope provided queries are also possible, mnemonics are listed under:
help cscope
This adds a list of the callers to the quickfix list, which you can open with:
:copen
Go to the line that interests you and hit enter to jump there.
To find callers of the function name currently under the cursor, add to your .vimrc:
function! Csc()
cscope find c <cword>
copen
endfunction
command! Csc call Csc()
and enter :Csc<enter> when the cursor is on top of the function.
TODO:
do it for the current function under cursor with a single command. Related: Show function name in status line
automatically add the nearest database (parent directories) when you enter a file: how to auto load cscope.out in vim
interactively open the call graph like Eclipse. Related: Generate Call-Tree from cscope database
A word of advice: I love vim, but it is too complicated for me to setup this kind of thing. And it does not take into account classes e.g. in C++. If a project matters enough to you, try to get the project working on some "IDE". It may involve some overhead if the project does not track the IDE configuration files (which are auto-changing blobs that pollute the repo...), but it is worth it to me. For C / C++, my favorite so far was KDevelop 4.
For that, Vim integrates with the cscope tool; see :help cscope for more information.
vi / . --- / is the search function in vi, and . will repeat the same command.
you could also use sed ( stream editor ) if it is a large file
sed
grep can get you the line numbers
read the man page
On OS X, I generated a set of ctags for the system includes using the following command:
ctags -f c -h ".h" -R --c-kinds=+p --fields=+iaS --extra=+q /usr/include
This was run inside of a ~/.vim/ctags/ directory, where I put all of the ctags I generate for system-wide header files (I also have stuff for ROS and CPP that I load conditionally, but that's neither here nor there).
Anyway. The ctags file is set correctly in my .vimrc, and vim can definitely see the ctags, but for some reason the autocomplete popup will only display results from #included header files if I write out the entire symbol and then start backspacing. As an example, if I #include <string.h> in a project, and then I want to call strlen(), and I start to type str in to the active vim buffer, I will only get results for symbols that are currently in the vim buffer. But, if I type out strlen and then start backspacing one or two characters and hit <C-n>, the popup menu will be populated with matches from any other included header files.
EDIT: Turns out, if I just hit "s" then <C-n>, it works as well. So the problem seems to be that it only works if the popup menu is launched manually. Which makes me think that it's a plugin problem (see below)
Additional information:
completeopt is set to completeopt=menuone,menu,preview,longest
I have OmniCppComplete, which I suppose could be interfering with the behavior. It is currently not being conditionally loaded for C++ files only. If you want me to edit and post my OmniCppComplete settings from my .vimrc, just ask.
I also have AutoComplPop installed, but I haven't done anything to configure it, so it's running with its default settings. Haven't really researched the plugin, so no idea if some of it's behavior could be interfering with the results.
I have AutoTag and TagBar installed, but those should only be fiddling with the current directory's local tagfile.
I'm honestly pretty new to Vim, and I just have no idea where to start debugging this issue, whether it be with a random plugin or with my .vimrc settings.
Vim has many specific completion mechanisms.
<C-n> and <C-p> use many sources defined by the complete option. By default, they will provide completion using the current and all loaded and unloaded buffers, tags and included files. While you can usually get quite useful suggestions with these, it is a bit of a "catch-all" solution: it is not reliable at all if you work on reasonably large projects.
<C-x><C-]> uses only tags so it may be a little more useful to you.
And there are many more, see :h ins-completion.
Omni completion is smarter: it typically runs a custom filetype-specific script that tries hard to provide meaningful completion. It is triggered by <C-x><C-o> and you can read about it in :h ft-c-omni. Omni completion is often a better choice when working with code.
Because you have two overlaping "auto"-completion plugins it's hard to say what completion mechanism is at work. You should disable those plugins and play around with the different completion mechanisms available to you.
I have not mastered this yet, but I do think the following observation may be of help.
Vim's default auto complete which can be quite noisy, often gets in the way of what you call with <C-x><C-o>. Specifically, I found myself calling up my tags based completions with <C-x><C-o> only to have them replaced with continued typing with Vim's default suggestions using my open buffers.
The suggestion of shutting off one of the plugins makes sense. In my case the key was how to shut down Vim's default behavior. I have seen several people (and to which I now include myself), set the length of the expression to a high number before triggering Vim's default. For me that is:
let g:deoplete#auto_complete_start_length = 99
... this way you eliminate the default layer of completions that comes and goes regardless of the commands you intended to inform your work.
This still feels like a hack but it helps keep my work focused on the tag-based completions.
FYI: I use NVIM on a Mac.
What are the most commonly used shortcuts used in gvim for C programming? For instance, how can I perform function name auto completion (without using the default word autocomplete). Could you please provide a cheatsheet or a tutorial?
I use snipMate alot for C++/C programming:
http://www.vim.org/scripts/script.php?script_id=2540
For function name auto completion you're probably stuck with ctrl+n ctrl+p or you can possibly try to get some omnicompletion working
http://vim.wikia.com/wiki/C%2B%2B_code_completion
This is what I was looking for: a vim cheatsheet!
I have a huge project, whole written in C language and I have a single make file that is used to compile it. The project C files contains lots of capitalize problems in it's header files, meaning there are tones of header files that were miss-spelled in lots of C files.
The problem is I need to migrate this project to compile on Linux machine and since Linux is case sensitive I got tones of errors.
Is there an elegant way which I can run make file in Linux and tell him to ignore case sensitive?
Any other solution will be welcome as well.
Thanks a lot.
Motti.
You'll have to fix everything by hand and rename every file or fix every place with #include. Even if you have a huge project (comparable with linux kernel), it should be possible to do this during a hour or two. Automation may be possible, but manual way should be better - because script won't be able to guess which name is right - filename, or the name used in #include.
Besides, this situation is a fault of original project developer. If he/she wasn't sloppy and named every header in every #include correctly, this wouldn't happen. Technically, this is a code problem similar to syntax error. The only right way to deal with it is to fix it.
I think it takes not too long to write a small script, which goes thru the directories first, then replaces C headers. Explained:
Scan the headers' folder and collect filenames.
Make a lowercase list of them. You have now original and locased pairs.
Scan the C source files and find each line contains "#include"
Lowercase it.
Find the lowercase filename in the list collected and lowercased from headers.
Replace the source line with the one collected from headers.
You should put the modified files into a separate folder structure, avoid overwriting the whole source with some buggy stuff. Don't forget to create target folders during the source tree scan.
I recommend a script language for that task, I prefer PHP, but just it's the only server-side script language which I know. Yep, it will run for a while, but only once.
(I bet that you will have other difficulties with that project, this problem is not a typical indicator of high quality work.)
Well I can only tell you that you need to change the case of those header files. I don't know that there is any way you can make it automatic but still you can use cscope to do it in a easier way.
http://www.linux-tutorial.info/modules.php?name=ManPage&sec=1&manpage=cscope
You can mount the files on a case-insensitive file system. FAT comes to mind. ntfs-3g does not appear to support this.
I use the find all and replace all functionality of Source Insight when i have to do complete replacement. But your problem seems quite big, but you can try the option to replace every header file name in all occurences of source files using the
"Find All" + "Replace" functionality. You can use notepad++ too for doing the same.
A long time ago there was a great tool under MPW (Macintosh Programmer's Workshop) called Canon. It was used to canonize text files, i.e. make all symbols found in a given refernce list have have the same usage of upper/lower case. This tool would be ideal for a task like this - I wonder if anything similar exists under Linux ?
When I work on someone else's code, I tipically need to abuse of grep in order to find data types declarations etc, and this usually makes me confused.
I'd like to have some tool which analyzes the source code and produces some graphviz-like drawing and allows me to follow dependencies.
Also I've found this on the internet, but I think is taylored for the linux kernel only.
Have you tried doxygen?
Doxygen can produce dot files, and you can build the documentation without changing the source code with the right options set in the Doxyfile.
Do you use an editor that can take advantage of tags ? In Emacs, I just type M-. to go to the definition of a symbol, and M-* to go back to where I was once I have read it. This also enables the command tags-search to grep among the files of the software project (very convenient if they are in multiple directories).