Hello, Steven Your test case is failed in my environment. I use boost 1.36.0 then I replaced my boost with 1.39.0 and found it works! What's the difference between them? 2009/5/23 Steven Watanabe

AMDG

梁绍池 wrote:

...

I've defined a function object as below:

struct BaseAddrLess : public std::binary_function { result_type operator() (const first_argument_type& lhs, const second_argument_type& rhs) const { return &lhs < &rhs; } };

and use as a compare function in ptr_set like this: ptr_set bset;

when the class Base is a abstract class the vc9 compiler will complain use of undefined type 'boost::result_of<F>'

What causes this problem? How to solve it?

Works for me. Do you have a minimal test case that fails? What version of Boost are you using?

#include <functional> #include

struct Base { virtual ~Base() = 0; };

Base::~Base() {}

struct Derived : Base {};

struct BaseAddrLess : public std::binary_function { result_type operator() ( const first_argument_type& lhs, const second_argument_type& rhs) const { return &lhs < &rhs; } };

int main() { boost::ptr_set bset; bset.insert(new Derived()); }

In Christ, Steven Watanabe

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