On 3/6/08, Jean-Pierre Bergamin wrote:

Hello

...

I couldn't figure out how to use a logical negation in the following situation.

struct IsConditionValid : public unary_function { public: bool operator() (const Event& event)const {} };

remove_copy_if(events.begin(), events.end(), back_inserter(result), IsConditionValid()); <-- how to negate the condition object?

What I really need is '! IsConditionValid()'.

How can it be done using may be boost::bind ?

If you already have a unary predicate (as your IsConditionValid functor), you can also use the std::not1 function to negate the predicate:

remove_copy_if( events.begin(), events.end(), back_inserter(result), not1(IsConditionValid()) );

Bind overloads the ! operator for your convenience

#include ...

remove_copy_if( events.begin(), events.end(), back_inserter(result), !boost::bind(IsConditionValid(), _1) );

Thanks Jean-Pierre. That did the trick.