The "Stack" interface

The example starts with the assumption that the class implementer has successfully built a SOM class library DLL, called "stack.dll", in the manner described in Section 5.6, "Creating a SOM Class Library," of Chapter 5, "Implementing Classes in SOM." The DLL implements the following IDL interface.

#include <somobj.idl>

interface Stack: SOMObject
{
    const long stackSize = 10;
    exception STACK_OVERFLOW{};
    exception STACK_UNDERFLOW{};
    boolean full();
    boolean empty();
    long top() raises(STACK_UNDERFLOW);
    long pop() raises(STACK_UNDERFLOW);
    void push(in long element) raises(STACK_OVERFLOW);

    #ifdef __SOMIDL__
    implementation
    {
      releaseorder: full, empty, top, pop, push;
      somDefaultInit: override;
      long stackTop;                  // top of stack index
      long stackValues[stackSize];    // stack elements
      dllname = "stack.dll";
    };
    #endif
};

This DLL could have been built without the knowledge that it would ever be accessed remotely (that is, built following the procedures in Chapter 5). Note, however, that some DLLs may require changes in the way their classes pass arguments and manage memory, in order to be used by remote clients (see the topic "Implementation Constraints" in section 6.5, "Implementing Classes").