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Rewrote the "adding more data" section to deal with missing destructor

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problem.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@1771 a95241bf-73f2-0310-859d-f6bbb57e9c96
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ejakowatz 2002-10-29 21:27:44 +00:00
parent 0e2e5d7f76
commit c1983bad48
1 changed files with 8 additions and 3 deletions
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11
docs/develop/ikteam/BinCompat.html
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@ -76,6 +76,7 @@ should be binary compatible in no time!
class BFoo {
public:
BFoo();
~BFoo();
void SomeFunc();
private:
int32 fBar;
@ -117,7 +118,7 @@ should be binary compatible in no time!
<code>int32</code>s worth of data: <code>fNewData1</code> through
<code>fNewData4</code>. The original implementation of BFoo has two extra
<code>int32</code>s which we can use, but that leaves us two <code>int32</code>s
short. What to do? The easiest thing to do is create a data structure to hold
short. What to do? The easiest thing is to create a data structure to hold
your new data and convert one of the <code>fUnused</code> items into a pointer
to that structure:
<code>
@ -155,8 +156,12 @@ should be binary compatible in no time!
}
</pre>
</code>
Voila! More data without making the class bigger. Notice the added
destructor; make sure you're cleaning up your new (dynamically allocated) data.
Voila! More data without making the class bigger. Make sure you're cleaning up
your new (dynamically allocated) data in the destructor. <b>NOTE:</b> this trick
will only work if the class originally had a destructor! Adding a destructor
after the fact won't work for existing apps (since they won't call it), leading
to memory leaks. Fortunately, there are very few instances in the BeAPI where a
class doesn't have a destructor already declared.
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