Code generation does not support recursive calls of thedeletemethod. Do not create an object of a certain class inside thedeletemethod for the same class. This usage might cause a recursive call ofdeleteand result in an error message.

The generated code always calls thedeletemethod, when an object goes out of scope. Code generation does not support explicit calls of thedeletemethod.

Initialize all properties ofMyClassthat thedeletemethod ofMyClassuses either in the constructor or as the default property value. Ifdeletetries to access a property that has not been initialized in one of these two ways, the code generator produces an error message.

Suppose a propertyprop1ofMyClass1is itself an object (an instance of another classMyClass2). Initialize all properties ofMyClass2that thedeletemethod ofMyClass1uses. Perform this initialization either in the constructor ofMyClass2or as the default property value. Ifdeletetries to access a property ofMyClass2that has not been initialized in one of these two ways, the code generator produces an error message. For example, define the two classesMyClass1andMyClass2:

classdefMyClass1 < handlepropertiesprop1end方法functionh = MyClass1(index) h.prop1 = index;endfunctiondelete(h) fprintf('h.prop1.prop2 is: %1.0f\n',h.prop1.prop2);endendend

classdefMyClass2 < handlepropertiesprop2endend

Suppose you try to generate code for this function:

functionMyFunction obj2 = MyClass2; obj1 = MyClass1(obj2);% Assign obj1.prop1 to the input (obj2)end

The code generator produces an error message because you have not initialized the propertyobj2.prop2that thedeletemethod displays.

The order of destruction of several independent objects might be different in MATLAB than in the generated code.

The lifetime of objects in the generated code can be different from their lifetime in MATLAB. MATLAB calls thedelete方法时an object can no longer be reached from any live variable. The generated code calls thedelete方法时an object goes out of scope. In some situations, this difference causesdeleteto be called later on in the generated code than in MATLAB. For example, define the class:

classdefMyClass < handle方法functiondelete(h)globalg% Destructor displays current value of global variable gfprintf('The global variable is: %1.0f\n',g);endendend

Run the function:

functionMyFunctionglobalg g = 1;obj = MyClass;obj = MyClass;% MATLAB destroys the first object hereg = 2;% MATLAB destroys the second object here% Generated code destroys both objects hereend

The first object can no longer be reached from any live variable after the second instance ofobj = MyClassinMyFunction. MATLAB calls thedeletemethod for the first object after the second instance ofobj = MyClassinMyFunctionand for the second object at the end of the function. The output is:

The global variable is: 1 The global variable is: 2

In the generated code, bothdeletemethod calls happen at the end of the function when the two objects go out of scope. RunningMyFunction_mexresults in a different output:

The global variable is: 2 The global variable is: 2

In MATLAB,persistentobjects are automatically destroyed when they cannot be reached from any live variable. In the generated code, you have to call theterminatefunction explicitly to destroy thepersistentobjects.

The generated code does not destroy partially constructed objects. If a handle object is not fully constructed at run time, the generated code produces an error message but does not call thedeletemethod for that object. For a System object™, if there is a run-time error insetupImpl, the generated code does not callreleaseImplfor that object.

MATLAB does call thedeletemethod to destroy a partially constructed object.