Re: Functor adaptor question

8 Jun 2006 01:26:04 -0700
Tim Roberts a =E9crit :

I had a case today where I needed a functor that was a bound member
function. Basically:

  class MyClass {

    ...bug free code omitted...

    void PrintMe( int x ) {
       printf( "%d\n", x );

    void A_Function() {
       std::vector<int> myList;
           bound_mem_fun( *this, PrintMe ); // bound_mem_fun is made up

Am I correct in my conclusion that there is no such adapter in the standa=


library? It looks like there is one in Boost, and it only took about 8
lines of code to implement it, but I don't want to reimplement it if there
is one built in that I missed.

You can do it with the standard library "mem_fun" facility, but it is
really clumsy, and you should prefer boost::bind if you can (btw, I
think boost::bind has been intergrated in CR1, so it will be part of
"official" C++ quite soon).

The STL version read like this:

for_each(myList.begin(), myList.end(),
             bind1st (mem_fun1<void, MyClass ,int>(&MyClass::PrintMe),

The boost version reads like this (ans it takes only 1 line!) :

#include <boost/bind.hpp>
using namespace boost;
for_each(myList.begin(), myList.end(),
         bind(&MyClass::PrintMe, this, _1));


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