Boost Users :
Subject: Re: [Boost-users] boost::any and const pointers
From: Dominique Devienne (ddevienne_at_[hidden])
Date: 2009-12-02 13:24:49
On Wed, Dec 2, 2009 at 10:55 AM, James C. Sutherland
> int main()
> Properties p;
> int i=1;
> int* j = get<int*>(p,"int*"); // I don't want this to compile
> const int* k = get<int*>(p,"int*"); // I want this to compile fine.
> Currently this whole code compiles without trouble, but I don't want to allow a non-const pointer to be extracted. Any ideas of how to accomplish this?
Thanks not possible AFAIK. The first compiles alright, but will fail
at runtime because the boost::any was constructed using a const int*.
By design all extractions are checked at runtime only, and the
typeid()/std::type_info of what you put in and what you try to get it
as must be the same. Given your code, you can't even do get<int>(p,
"int"), because a const int was put in, not an int (see your set()
impl), and typeid(int) != typeid(const int). --DD
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