Question

If I have a function that takes int *&, what does it means? How can I pass just an int or a pointer int to that function?

function(int *& mynumber);

Whenever I try to pass a pointer to that function it says:

error: no matching function for call to 'function(int *)'
note: candidate is 'function(int *&)'

Answer 1

It’s a reference to a pointer to an int. This means the function in question can modify the pointer as well as the int itself.

You can just pass a pointer in, the one complication being that the pointer needs to be an l-value, not just an r-value, so for example

int myint;
function(&myint);

alone isn’t sufficient and neither would 0/NULL be allowable, Where as:

int myint;
int *myintptr = &myint;
function(myintptr);

would be acceptable. When the function returns it’s quite possible that myintptr would no longer point to what it was initially pointing to.

int *myintptr = NULL;
function(myintptr);

might also make sense if the function was expecting to allocate the memory when given a NULL pointer. Check the documentation provided with the function (or read the source!) to see how the pointer is expected to be used.