One interesting thing that rtags does is provide a gcc/clang wrapper script. You make symlinks to it called cc/c++/gcc/g++/etc. in a folder that's in PATH ahead of wherever gcc/clang proper live. When invoked, the script submits an appropriate tags job to the rtags server, complete with compile flags actually used, then passes the command line on to the appropriate tool so that the compile actually gets done.

So quite often you won't need to do anything. (If you use CMake, you will have to rebuild your Ninja/make files after first setting this up.)

I didn't find rtags perfect. There were a few files that it simply never seemed to create tags for, and the rtags setup is complicated enough that I couldn't quickly figure out why, so I just put up with it. But when it works, it works very well...

(This sort of thing seems to be par for the course with this kind of tool. I've seen a number of people complain about how terrible Visual Studio's code browsing is, for example, but it's been a long time since I've had a problem with it...)