Can an unnamed parameter of function have a default value?

Question

Is the following code legal in C++?

void f(void* = 0)
{}

int main()
{
    f();
}

Which page of the C++ standard states that this usage is lega

Answer 1

Not only is it legal, it could actually be quite useful depending on your coding style.

Default parameters are only meaningful in a function declaration.

Named parameters are only meaningful in a function definition.

f.h:

void f(void*=nullptr);

f.cc

void f(void* x)
{
...
}