Reason behind using (void)someInt; in code

Question

I am reading some code of a library I am using, and I found that in a function this was used:

void someFunction(Foo& a, int index, int partId)
{
    (void) partId;
    (void) index;
    // more code
}

Anyone knows why? Thanks.

Answer 1

To avoid a compiler warning/error indicating that the variable was unused in the function body. It's a style choice, the other way to achieve the same effect would be to leave the variable un-named:

void someFunction(Foo& a, int /*index*/, int /*partId*/)