# Pass argument "by-reference"

This sections shows how to use function that would have been defined using the "by-reference" 
prototype, which is specific to C++. This macro is also detailled 
[](#use_cases_howto_py_pass_reference_py).

{{
    "```{literalinclude} " + parent_dir 
    + "/roottest/uranie/doc/overview/use_cases/python/howtoPassReference.py\n"
    + ":language: python\n"
    + ":lines: 1-5,11-23\n"
    + "```"
}}

The macro shown above, is an example of how to load a function and use it in a single-point estimation. 
Its result is discussed in [](#use_cases_howto_py_pass_reference_py).