ctags can not recognize c++ template

Question

my ctags version is 5.8

i generate my ctags using :

ctags -R --sort=yes --language-force=c++ --c++-kinds=+plx --fields=+iaS --extra=+q .

and i set my vimrc like this

set tags=./tags,./..tags,./**/tags

but when i press ctrl+], vim can not jump to the class template or funciton template

i searched the tags file , there is no such tag generated. so I am writing here for your help. thank you !