How can I track cases when a pointer from a "new" expression is passed to dynamic_cast?

Question

Recently I found the following while reviewing some old code:

auto_ptr<DerivedClass> pointer = dynamic_cast<CBase*>( new CDerived() );

aside from the fact that this code is meaningless in valid cases (in valid cases class Derived is derived from class Base and no dynamic_cast is necessary) there's a problem with object ownership. If for whatever reason dynamic_cast returns a null pointer the auto_ptr will not be bound to the created object and the object will be leaked.

Is there some technique to help prevent such errors like making a compiler issue a warning or anything like that?

Something like grep? Or do you need a more advanced way? – rve Mar 31 '11 at 08:23 — rve, Mar 31 '11 at 08:23

Ben · Accepted Answer · 2011-04-02T12:19:03.827

3

Get rid of all your dynamic_casts.

All of them.

Then no tracking will be necessary.

edited Apr 02 '11 at 12:19

answered Apr 02 '11 at 12:12

Ben

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score 1 · Answer 2 · answered Mar 31 '11 at 08:31

1

If you can't find anything already available you can also add your own rule to cpp check

answered Mar 31 '11 at 08:31

rve

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How can I track cases when a pointer from a "new" expression is passed to dynamic_cast?

2 Answers2