Question

I have digging through the C# code generated by SWIG for Quantlib and came across the following code that gave me a humbling moment.

Each of the generated classes implement IDisposable, and each of the generated classes have this convention pointed out below.

public class MultiPath : IDisposable { // MultiPath is interchangable
  private HandleRef swigCPtr;
  protected bool swigCMemOwn;

  internal MultiPath(IntPtr cPtr, bool cMemoryOwn) {
    swigCMemOwn = cMemoryOwn;
    swigCPtr = new HandleRef(this, cPtr);
  }

  internal static HandleRef getCPtr(MultiPath obj) {
    return (obj == null) ? new HandleRef(null, IntPtr.Zero) : obj.swigCPtr;
  }

  ~MultiPath() { // <---- 
    Dispose();
  }

  public virtual void Dispose() {
    lock(this) {
      if (swigCPtr.Handle != IntPtr.Zero) {
        if (swigCMemOwn) {
          swigCMemOwn = false;
          NQuantLibcPINVOKE.delete_MultiPath(swigCPtr);
        }
        swigCPtr = new HandleRef(null, IntPtr.Zero);
      }
      GC.SuppressFinalize(this);
    }
  }
  // snip
}

If I’m reading this correctly, the bitwise complement operator is applied to the constructor of the class, so my questions are

1. Why is the purpose of ~ operator in this example?
2. What effect does it have?
3. What are the correct situations to use such an operator and technique?

Edit:

Just for clarity, the ~ is this case is called a Destructor. Thanks’s @Arcturus.

Answer 1

Its the destructor!

In simple terms a destructor is a
member that implements the actions
required to destruct an instance of a
class. The destructors enable the
runtime system, to recover the heap
space, to terminate file I/O that is
associated with the removed class
instance, or to perform both
operations.