c-recognize-<>-arglists is a variable defined in `cc-engine.el'.
Its value is

  • Automatically becomes buffer-local when set.

Non-nil means C++ style template arglists should be handled. More
specifically, this means a comma separated list of types or
expressions surrounded by "<" and ">". It's always preceded by an
identifier or one of the keywords on `c-<>-type-kwds' or
`c-<>-arglist-kwds'. If there's an identifier before then the whole
expression is considered to be a type.