Emacs as C++ IDE, easy way

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CREATED: <2016-08-25>

UPDATED: <2017-01-31 Tue>

This is a newbie friendly solution which works at Linux/OSX/Cygwin (should work at Windows, but I don't develop at Windows).

Setup is minimum. Only GNU Global and two Emacs plugins are required:

Here is the step to step guide.

1 Step 1, create sample projects for experiment

Say I have two projects ~/proj1 and ~/proj2. Both projects will use third party library C++ header files from read-only directory /usr/include.

A new directory ~/obj to store the index files of third party libraries.

mkdir -p ~/{proj1,proj2,obj}

The content of ~/proj2/lib.cpp,

void proj2_hello(int a2, char* b2) {
}

The content of ~/proj1/main.cpp,

void proj1_hello(int a1, char* b1) {
}

int main(int argc, char *argv[]) {
    return 0;
}

2 Step 2, scan C++ code and setup Emacs

Run below command in shell to scan code,

cd /usr/include && MAKEOBJDIRPREFIX=~/obj gtags && cd ~/proj1 && gtags && cd ~/proj2 && gtags

After setting up the corresponding Emacs plugins (minimum setup copied from their website is enough), insert below code into ~/.emacs,

;; Please note `file-truename' must be used!
(setenv "GTAGSLIBPATH" (concat "/usr/include"
                               ":"
                               (file-truename "~/proj2")
                               ":"
                               (file-truename "~/proj1")))
(setenv "MAKEOBJDIRPREFIX" (file-truename "~/obj/"))
(setq company-backends '((company-dabbrev-code company-gtags)))

3 Usage

Use the Emacs plugins as usual.

But you need install latest company built on 25th August because I fixed a company issue yesterday.

Screenshot,

cpp-gtags-demo-nq8.png

4 Technical Details (Optional)

Check GNU Global manual to understand environment variables GTAGSLIBPATH and MAKEOBJDIRPREFIX.

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