remove_if with boost::bind is slow

boost, boost-bind, c++, ref, remove-if

Solution

Try replacing the call to `std::remove_if` with `std::list::remove_if`. The latter should only copy some pointers from the preceding and succeeding elements, instead of trying to move the elements to the end of the list, which is the cause of the multiple allocations you're seeing. An additional benefit is that since it is a member function of `std::list`, it actually removes (i.e. erases) the elements matching your criterion.

class MyClass
{
    bool isDone(MyData& myData)
    {
        return myData.isDone();
    }

    void removeIfDone(std::list<MyData>& myList)
    {
        myList.remove_if( boost::bind( &MyClass::isDone, this, _1 ) );
    }
};

Problem

I have a std::list of classes and want to remove entries that are marked for delete. I am using std::remove_if and erase. ``` class MyClass { bool isDone(MyData& myData) { return myData.isDone(); } void removeIfDone(std::list<MyData>& myList) { std::list<MyData>::iterator it = remove_if(myList.begin(), myList.end(), boost::bind(&MyClass::isDone, this, _1)); myList.erase(it, myList.end()); } }; ``` I am running on a small processor for which memory allocation and deallocation is very expensive. This remove is calling new and delete thousands of times in my application. I have previously used `boost::ref` when passing a non-trivial variable as a bind parameter but in this case I think it is probably the creation and destruction of the functor itself or the copying of it which is causing the problem. I would like to do something like ``` boost::bind(&MyClass::isDone, boost::ref(this), boost::ref(_1)); ``` I can't find documentation on what is being created and destroyed. So my simple question is how do I make this more efficient?

Original source