You never said this. And even if you did not stop, you answer strongly suggest that you do not use Emacs for serious development anymore, and was out of date with current state of Emacs. If you actually use it, you would know that none of my demos use Clang.
Yes, since you spread failed information, and I had to post to correct it. There are many things that could not be done in those IDEs you listed, i.e. to debug random binary outside of a project. Did you tried it Ctrl + H for finding files? Completely unnecessary complicated with tons of checkboxes, and slow to search. It does not show me result instantly; meanwhile in Emacs, I could do this: Open file at point anywhere, even in plain text file: http://tuhdo.github.io/static/helm-projectile/helm-projectil...
In debugging, Eclipse is no difference than Emacs; both use GDB. For compiling, Eclipse also uses external debugger. The only thing that makes it an IDE is its internal parser, that is broken for large projects and Emacs also has a C/C++ parser anyway. What make Emacs less IDEish than Eclipse?