Overriding Destructors - Revision history

Krashan: Added link to yet to be written Polish version.

2011-01-26T06:39:16Z

Added link to yet to be written Polish version.

AusPPC at 05:50, 7 January 2011

2011-01-07T05:50:46Z

Krashan: Contents.

2011-01-04T13:06:50Z

Contents.

New page

''Grzegorz Kraszewski''

The only task of a destructor is freeing resources allocated in the constructor and other methods (some resources may be allocated on-demand only). In any case the destructor must leave the object in the same state as right after ''DoSuperMethod()/DoSuperNew()'' in the constructor. After that the destructor calls a super class destructor. The destructor receives an empty message.

IPTR MyClassDispose(Class *cl, Object *obj, Msg msg)
{
struct MyClassData *d = (struct MyClassData*)INST_DATA(cl, obj);

if (d->ResourceA) FreeResourceA();
if (d->ResourceB) FreeResourceB();
if (d->ResourceC) FreeResourceC();
return DoSuperMethodA(cl, obj, msg);
}

The example destructor follows an example of constructor in the [[Overriding Constructors]] article. Three resources obtained in the constructor are freed here. The destructor is prepared for partially constructed object, every resource is checked against ''NULL'' before freeing. If for some type of resource NULL is a valid handle, an additional flag may be added to the object instance data area.

← Older revision		Revision as of 06:39, 26 January 2011
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	''Grzegorz Kraszewski''		''Grzegorz Kraszewski''
		+	----
		+	<small>This article in other languages:[[Przeciążanie destruktorów\|Polish]]</small>

@@ Line 2: / Line 2: @@
-The only task of a destructor is freeing resources allocated in the constructor and other methods (some resources may be allocated on-demand only). In any case the destructor must leave the object in the same state as right after ''DoSuperMethod()/DoSuperNew()'' in the constructor. After that the destructor calls a super class destructor. The destructor receives an empty message.
+The only task of a destructor is freeing resources allocated by the constructor and other methods (some resources may be allocated on-demand only). In any case the destructor must leave the object in the same state as right after ''DoSuperMethod()/DoSuperNew()'' in the constructor. After that the destructor calls a super class destructor. The destructor receives an empty message.
   IPTR MyClassDispose(Class *cl, Object *obj, Msg msg)
@@ Line 14: / Line 14: @@
+  }
-The example destructor follows an example of constructor in the [[Overriding Constructors]] article. Three resources obtained in the constructor are freed here. The destructor is prepared for partially constructed object, every resource is checked against ''NULL'' before freeing. If for some type of resource NULL is a valid handle, an additional flag may be added to the object instance data area.
+The example destructor follows the example of the constructor in the [[Overriding Constructors]] article. Three resources obtained in the constructor are freed here. The destructor is also prepared for a partially constructed object, every resource is checked against ''NULL'' before freeing. If for some type of resource NULL is a valid handle, an additional flag may be added to the object instance data area.