Re: [Boost-users] boost::bind issues revisited

Subject: Re: [Boost-users] boost::bind issues revisited
From: Nathan Ridge (zeratul976_at_[hidden])
Date: 2013-04-22 03:07:34

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> Date: Mon, 22 Apr 2013 00:52:27 -0600
> From: tyler_at_[hidden]
> To: boost-users_at_[hidden]
> Subject: [Boost-users] boost::bind issues revisited
>
> oHello all:
> I'm kind of at a loss here. It looks like ther'es an issue with
> boost::bind somewhere in the mess of 500 templates and 90 screens of
> errors and I don't know enough about the mess to untangle it. Any info
> would be awesome. First, the code:
>
> sgroup->AddEntry(new OlcStringEntry("name", "Sets the name of the
> object", OF_NORMAL,
> boost::bind(&StaticObject::GetName, _1),
> <159> boost::bind(&StaticObject::SetName, _1, _2)));
>
> the 159 I denoted is useful in the errors later.
> Now the rest of the code I'm using:
>
> typedef boost::function<std::string ()> StringGetter;
> typedef boost::function<void (const std::string&)> StringSetter;
>
> class IOlcEntry
> {
> protected:
> std::string _name;
> std::string _help;
> FLAG _flag;
> public:
> IOlcEntry(const std::string &name, const std::string &help, FLAG flag)
> {
> _flag = flag;
> _name = name;
> _help = help;
> }
> ~IOlcEntry() {}
> };
>
> class OlcStringEntry:public IOlcEntry
> {
> protected:
> StringGetter _getter;
> StringSetter _setter;
> public:
> OlcStringEntry(const std::string &name, const std::string &help, FLAG
> flag, const StringGetter getter, const StringSetter setter)
> :IOlcEntry(name, help, flag)
> {
> _setter = setter;
> _getter = getter;
> }
> };

Looks like you are trying to pass "boost::bind(&StaticObject::GetName, _1)",
which is a 1-argument function object, as the argument for a parameter of
type "StringGetter", which is a typedef for "boost::function<std::string ()>", 
which is a 0-argument function object. 

You have a similar problem for the setter.

Perhaps you meant to bind the getter and setter to a specific instance of
StaticObject? In that case, assuming 'my_instance' is that instance, you 
should write:

boost::bind(&StaticObject::GetName, my_instance)

and

boost::bind(&StaticObject::SetName, my_instance, _1)

and then you'll have function objects that are assignable to StringGetter
and StringSetter, respectively.

Regards,
Nate