The slight difference is that the order of the arguments is stated in the api of the library (which does not solve the problem though). The problem may be solve

The slight difference is that the order of the arguments is stated in the api of the library (which does not solve the problem though). The problem may be solved by passing an iod as single argument: fun(iod(arg1_ = 1, arg2_ = "foo")); or by using method chaining : http://www.parashift.com/c++-faq-lite/named-parameter-idiom.html http://www.parashift.com/c++-faq-lite/named-parameter-idiom....