2009-10-19 17:00:38 +02:00
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it() There is a special cast to do away with the tt(const)
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type-modification:
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centt(const_cast<type>(expression))
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it() A third cast is used to change the em(interpretation) of information:
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centt(reinterpret_cast<type>(expression))
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it() And, finally, there is a cast form which is used in combination with
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polymorphism (see chapter ref(POLYMORPHISM)). The
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centt(dynamic_cast<type>(expression))
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is performed run-time to convert, e.g., a pointer to an object of a
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certain class to a pointer to an object further down its so-called em(class
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hierarchy). At this point in the em(Annotations) it is a bit premature to
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discuss the tt(dynamic_cast), but we will return to this topic in section
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ref(DYNAMICCAST).
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)
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2006-09-04 10:26:34 +02:00
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The ti(const_cast<type>(expression)) operator is used to undo the
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tt(const)-ness of a (pointer) type. Assume that a function
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tt(fun(char *s)) is available, which performs some operation on its
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tt(char *s) parameter. Furthermore, assume that it's em(known) that the
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function does not actually alter the string it receives as its argument. How
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can we use the function with a string like tt(char const hello[] = "Hello
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world")?
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Passing tt(hello) to tt(fun()) produces the warning
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centt(passing `const char *' as argument 1 of `fun(char *)' discards const)
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which can be prevented using the call
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centt(fun(const_cast<char *>(hello));)
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