Invoking C++ with pointer param from C#

[Kenneth Porter]

If a C++ method takes a pointer to an int for output (for example), how
should C# pass the int into which it wants the result returned?

(I'll post some test code shortly. I'm writing the question from memory
after a meeting yesterday with a C# developer and need to recreate his two
test projects. I've got some C++ that he needs to invoke. I'm new to C# but
have dealt with low-level cross-language issues in other languages.)

In C++, the method signature would look like one of:

void fooptr(int* x);
void fooref(int& x);

How would C# invoke these?

[=?ISO-8859-1?Q?Arne_Vajh=F8j?=]

Kenneth Porter wrote:

If a C++ method takes a pointer to an int for output (for example), how
should C# pass the int into which it wants the result returned?

In C++, the method signature would look like one of:

void fooptr(int* x);
void fooref(int& x);

How would C# invoke these?

[DllImport(@"C:\ptr.dll")]
private static extern void fooptr(ref int x);
[DllImport(@"C:\ptr.dll")]
private static extern void fooref(ref int x);

seems to work for me.

Arne