Term not evaluated to a function in C++ - c++

Question

I have following code, which i taken from Boost and simplified for my project. Please accept my aplogies for pasting complete code, i done it so that it will be easy to answer my question. While compiling following code in VS 2008 i am getting followoing error.
error C2064: term does not evaluate to a function taking 3 arguments
I am expecting addOptions retruns OptionsInit object which call function operator with three arguments but that is not happening, can any one please find bug. Thanks in advance.
namespace MyInfrastructure
{
namespace Internal
{
class OptionDescrp;
class OptionsInit;
}
class OptionsCollection
{
public:
OptionsCollection(std::string optCollName);
Internal::OptionsInit addOptions();
private:
// avoid copying and assignment.
// Prohibit copy
OptionsCollection( const OptionsCollection& );
OptionsCollection& operator = (const OptionsCollection& );
void add(Internal::OptionDescrp* desc) {m_options.push_back(desc);}
std::vector<Internal::OptionDescrp* > m_options;
std::string m_optCollName;
friend class Internal::OptionsInit;
};
}
////////////
#include <string>
#include <vector>
#include <assert.h>
#include "PrgmOptions.h"
namespace MyInfrastructure
{
namespace Internal
{
class OptionDescrp
{
public:
OptionDescrp(std::string pcOptname, std::string description, bool isOptValueReq);
virtual ~OptionDescrp(){ };
private:
std::string m_shortName; // option short name.
std::string m_longName; // option long name.
std::string m_description;// option description.
};
class OptionsInit
{
public:
OptionsInit(OptionsCollection* coll){ owner = coll; }
OptionsInit& operator()(std::string name, std::string description, bool isOptValReq);
private:
OptionsCollection* owner;
};
}
/////
namespace MyInfrastructure
{
OptionsCollection::OptionsCollection(std::string optCollName) : m_optCollName(optCollName) {}
Internal::OptionsInit OptionsCollection::addOptions()
{
return Internal::OptionsInit(this);
}
}
namespace MyInfrastructure
{
namespace Internal
{
// Class Options description definitions.
OptionDescrp::OptionDescrp(std::string pcOptname, std::string description, bool isOptValueReq)
: m_description(description)
{
std::string name(pcOptname);
std::string::size_type n = name.find(',');
if (n != std::string::npos)
{
assert(n == name.size()-2);
m_longName = name.substr(0, n);
m_shortName = '-' + name.substr(n+1,1);
}
else
{
m_longName = name;
}
}
// Class Options Init definitions.
OptionsInit& OptionsInit::operator()(std::string name, std::string description, bool isOptValReq)
{
OptionDescrp* opt = new OptionDescrp(name, description, isOptValReq);
owner->add(opt);
return *this;
}
}
}
//////
int main(void)
{
MyInfrastructure::OptionsCollection desc("myoptions");
**desc.addOptions()("help", "produce help message", false); // error is thrown here**
return 0;
}

Answer 1

The example code in the question compiles without errors with Visual 2008, gcc, Visual 2003 when we copy all in a single file.
You have error C2064, it is probably because you either have a #define or another definition somewhere in other headers that you did not include in your sample, or that somehow you are not compiling exactly the sample code.
Try to copy all the sample code in a single file and compile that.

Answer 2

Interesting code: OptionsInit returned by addOptions() is a temporary. You are then calling a non-const method on it, which is allowed, but it returns a non-const reference to itself which is also allowed because it's a non-const method. But that means essentially you "backdoor" binding a non-const reference to a temporary...
I assume the two asterisks before desc.addOptions are not really in your code as there is no operator* overloaded here.
Perhaps if you make operator() const and return const-reference it will work.

Answer 3

problem is with VS2008. I compiled with VS2010, it compiled fine. Thanks all for the inputs.