void pointer as a parameter

[hopesfall]

I want to have a function that has a pointer to an int/double/string so I thought I'd use a void pointer like so:

int someFnc(int a, int b, const void *key){
  // take care of converting key into appropriate type in here
}

And when I want to use this function I'd like to be able to do something like this:

main{
...
  int myKey;
  someFnc(1,2,myKey);
]

But I get a compiler error telling me:
invalid conversion from 'int' to 'const void' -[fpermissive]

Do I need to convert myKey into a void pointer before passing it as an argument?

Edit: Why does passing myKey like this work?
someFnc(1,2,&myKey);

[binarybob350]

Since the parameter is a void * you need to pass in the address of something. If you cast an integer into a void * it would most likely be an invalid pointer.