Re: mem_fun fun

From:
"Victor Bazarov" <v.Abazarov@comAcast.net>
Newsgroups:
comp.lang.c++
Date:
Tue, 18 Sep 2007 15:38:57 -0400
Message-ID:
<fcp9gf$7n7$1@news.datemas.de>
flopbucket wrote:

I am having some problem using std::bind1st() and mem_fun. I want to
bind member function calls to some kind of functor so it can be called
later.

The following works fine for me:

class Foo
{
       std::string name;
public:
       Foo() : name("mike") {}

       std::string getName()
       {
               return name;
       }

       void setName(std::string n)
       {
               name = n;
       }
};

typedef std::binder1st<std::mem_fun1_t<void, Foo, std::string > >
SetterFunc;

main()
{
       Foo foo;

       SetterFunc f = std::bind1st(mem_fun(&Foo::setName), &foo);

       std::string test("testing");
       f(test);

       std::cout << "after call, name is " << foo.getName() <<
std::endl;
}

But when I want to bind the getName() method, I have lots of trouble:

typedef std::binder1st<std::mem_fun_t<std::string, Foo > > GetterFunc;
GetterFunc y = std::bind1st(mem_func(&Foo::getName), &foo);


What kind of trouble? Why couldn't you post non-working code instead?

I think I don't want to use bind1st because the getName() method takes
no parameters? Is there a std::bind() ?


Why wouldn't you? 'bind1st' makes sure that the member function is
called with the particular instance, 'foo'.

Also, what if setName() takes "const std::string&" instead of just
"std::string" ? Do I need mem_fun_ref or some const variation of it?


Probably. Have tried it an failed or what?

V
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