This article will describe using auto-highlight-symbol package which highlight symbol at the cursor.
1 Install auto-highlight-symbol package
Install auto-highlight-symbol package with M-x package-list-packages.
auto-highlight-... 1.55 available Automatic highlighting current symbol minor mode
Add auto-highlight-symbol-mode to each major mode. c++-mode is as below.
(add-hook 'c++-mode-hook 'auto-highlight-symbol-mode)
all major mode is as below.
(add-hook 'after-init-hook 'global-auto-highlight-symbol-mode)
3 Execution result
All locations of "argc" are highlighted.