Question regarding int* const in function call.

[Andrew Isaverdian]

void MyFunc(int* const ptr)
{
ptr = new int[10];
........
}

In program

int main()
{
int a = 0;
int* ptr1 = &a;
...................
MyFunc(ptr1); // gcc, for example, complains that "new int[10]"
contradicts
//constantess of the function's argument
(pointer in our case).
// However, we are dealing with a private copy
of the pointer
//anyway (???)
}

[Phlip]

Andrew Isaverdian wrote:

Are you trying to pass a pointer by reference? int *& ptr?

void MyFunc(int* const ptr)
That is a "top-level const", meaning "ptr is a constant pointer to an
integer". The pointer is constant, not the integer. int const * ptr would
mean "ptr is a pointer to a constant integer".

There's never a reason to put a top-level const at the interface to a
function.
{
ptr = new int[10];

And that tries to change the pointer, not the pointed-to thing. It's const,
so you get an error.

--
Phlip
http://c2.com/cgi/wiki?ZeekLand <-- NOT a blog!!!

[Jonathan Mcdougall]

Andrew Isaverdian wrote:

void MyFunc(int* const ptr)
This is a const pointer to an int, which means you cannot change the
pointer, but you could change what's pointed at.
{
ptr = new int[10];
Therefore, this is illegal, but

*ptr = 2;

would be ok.
}

Jonathan