https://stackoverflow.com/questions/34519318/c-address-of-fu... suggests it's guaranteed by the standard to be OK.

In the standard at https://web.archive.org/web/20181230041359if_/http://www.ope...

    6.5.3.2 Address and indirection operators
    Constraints
    1 The operand of the unary & operator shall be either a 
    function designator, the result of a [] or unary
    \* operator, or an lvalue that designates an object that
    is not a bit-field and is not declared with the
    register storage-class specifier.

So as the parameter is an lvalue it is guaranteed to work with the & operator.