SC2Mapster

void fn_prototype(int a);

void some_function_that_must_match_above_signature(int param)
{
}

void main()
{
    funcref<fn_prototype> ref;
    ref = some_function_that_must_match_above_signature;
    ref(1);
}

Some further explanation about _ref thingies can be found here:
https://www.sc2mapster.com/forums/development/galaxy-scripting/148197-passing-arrays-as-parameters