doomemacs/modules/lang/cc/README.org

#+TITLE: :lang cc

This module adds support for the C-family of languages: C, C++, and Objective-C.

+ Code completion (~company-irony~)
+ eldoc support (~irony-eldoc~)
+ Syntax-checking (~flycheck-irony~)
+ Code navigation (~rtags~)
+ File Templates ([[../../feature/file-templates/templates/c-mode][c-mode]], [[../../feature/file-templates/templates/c++-mode][c++-mode]])
+ Snippets ([[https://github.com/hlissner/emacs-snippets/tree/master/cc-mode][cc-mode]], [[https://github.com/hlissner/emacs-snippets/tree/master/c-mode][c-mode]], [[https://github.com/hlissner/emacs-snippets/tree/master/c++-mode][c++-mode]])
+ Several improvements to C++11 indentation and syntax highlighting.

#+begin_quote
C contends with Haskell and Ruby for my favorite language. That said, it's more
accurate to say I write C, but a C++ feature or three.

The module provides nominal support for Objective-C, which I really only use to
inspect generated glue code for iOS mobile apps. Otherwise, I prefer Swift.
#+end_quote

* Table of Contents :TOC:
- [[#install][Install]]
  - [[#irony-server][irony-server]]
  - [[#rtags][rtags]]
- [[#configure][Configure]]
  - [[#compile-settings][Compile settings]]

* Install
This module requires:

+ irony-server
+ rtags

** irony-server
Irony powers the code completion, eldoc and syntax checking systems.

*** MacOS
Due to linking issues, MacOS users must compile irony-server manually:

#+BEGIN_SRC sh :tangle (if (doom-system-os 'macos) "yes")
brew install cmake
brew install llvm  # 1gb+ installation! May take a while!

git clone https://github.com/Sarcasm/irony-mode irony-mode
mkdir irony-mode/server/build
pushd irony-mode/server/build

DEST="$HOME/.emacs.d/.local/$(hostname)/etc/irony-server/"
cmake -DCMAKE_INSTALL_RPATH_USE_LINK_PATH=ON \
      -DCMAKE_INSTALL_PREFIX="$DEST" ../
cmake --build . --use-stderr --config Release --target install

install_name_tool -change @rpath/libclang.dylib \
    /usr/local/opt/llvm/lib/libclang.dylib \
    "$DEST/bin/irony-server"

# cleanup
popd
rm -rf irony-mode
#+END_SRC

*** Arch Linux
#+BEGIN_SRC sh :tangle (if (doom-system-os 'arch) "yes")
sudo pacman --needed --noconfirm -S clang cmake
#+END_SRC

Then run ~M-x irony-install-server~ in Emacs.

** rtags
Code navigation requires an [[https://github.com/Andersbakken/rtags][rtags]] server (~rdm~) installed and running. This
should be available through your OS's package manager.

This module will auto-start ~rdm~ when you open C/C++ buffers (so long as one
isn't already). If you prefer to run it yourself, outside of Emacs:

#+BEGIN_SRC sh
rdm &
rc -J $PROJECT_ROOT  # loads PROJECT_ROOT's compile_commands.json
#+END_SRC

* Configure
** Compile settings
By default, a set of default compile settings are defined in
~+cc-compiler-options~ for C, C++ and Objective C. Irony, rtags and flycheck
will fall back to these.

To make these tools aware of project specific build settings, you need a JSON
[[https://sarcasm.github.io/notes/dev/compilation-database.html#ninja][compilation database]] present (i.e. a ~compile_commands.json~ file).

There are [[https://sarcasm.github.io/notes/dev/compilation-database.html][many ways to generate one]]. I use [[http://www.cmake.org/][CMake]] and [[https://github.com/rizsotto/Bear][bear]]:

#+BEGIN_SRC sh
# For CMake projects
cmake -DCMAKE_EXPORT_COMPILE_COMMANDS=ON .

# For non-CMake projects
make clean
bear make
#+END_SRC

#+begin_quote
Use ~M-x +cc/reload-compile-db~ to reload your compile db in an already-open
C/C++/ObjC buffer.
#+end_quote