lukasz-m-maciejewski / cmake-ide

Use Emacs as a C/C++ IDE

cmake-ide

CppCon 2015 Lighning talk on cmake-ide.

cmake-ide is a package to enable IDE-like features on Emacs for CMake projects. This includes autocompletion and on-the-fly syntax checking in Emacs for CMake projects with minimal configuration. It depends on flycheck and auto-complete-clang. Support might be added for other packages later (e.g. flymake, company).

It works by running CMake in Emacs in order to obtain the necessary -I and -D compiler flags to pass to the other tools. Since all the dependencies are specified in the CMake scripts, there is no need to maintain a parallel dependency tracking system for Emacs. Just ask CMake.

Features

• Sets variables for auto-complete-clang and flycheck for a CMake project automagically. Hardly any configuration necessary.
• Automatically reruns CMake when a file is saved. Great when using CMake file globs to pick up newly created files, but needs cmake-ide-dir to be set.
• cmake-ide-delete-file allows you to have the same convenience when deleting files. I can't figure out a better way to do this. Obviously simply deleting the file means having to run CMake again manually for it to register the change in the list of files to be compiled.
• If cmake-ide-dir is set, it is considered to be the build directory to run CMake in. Additionally, this will cause cmake-ide-compile to compile the project there. It automatically detects Ninja and Make builds and sets the compile command accordingly. The command to use can be customised by setting the cmake-compile-command variable.
• cmake-ide can make usage of rtags for finding definitions, also using clang. If (require 'rtags) is called before cmake-ide-setup, it will automatically start the rtags server (rdm) and call rc -J to index the project files for 0-config "jump to definition" and everything else rtags offers. This only works if both rdm and rc and in the system path or if cmake-ide-rdm-executable and cmake-ide-rc-executable are customized correctly.

Installation

Install from MELPA or MELPA Stable with:

M-x package-install RET cmake-ide.

Usage

Add this to your .emacs / init.el:

(require 'rtags) ;; optional, must have rtags installed
(cmake-ide-setup)

If cmake-ide-clang-flags-c or cmake-ide-flags-c++ are set, they will be added to ac-clang-flags. These variables should be set. Particularly, they should contain the system include paths (e.g. '("-I/usr/include/c++/4.9.1" "..."). For a system with gcc, you can get this information by running gcc -v -xc++ /dev/null -fsyntax-only (it's the same prerequisite for auto-complete-clang to work, since that's how clang itself works).

And... that's it. It works by calling cmake and parsing the resulting JSON file with compiler flags. Set cmake-ide-dir to your project's root directory and you won't have to call CMake manually again (except for the first time to specify options). Best done with directory local variables.

Related Projects:

• cpputils-cmake.
• My CMake modules for emacs. cmake-ide is definitely better.