compilation error with function template parameter

[subramanian100in]

The following quesion is NOT a HOMEWORK problem.

Consider the following x.cpp:

#include <cstdlib>
#include <iostream>

using namespace std;

template<class T>
inline void fn(void (T::*memfnPtr)())
{
return;
}

class Test
{
public:
void member();
void member() const;
};

inline void Test::member(void)
{
cout << "Test::member() called" << endl;

return;
}

inline void Test::member(void) const
{
cout << "Test::member() const called" << endl;

return;
}

int main()
{
fn(&Test::member);

return EXIT_SUCCESS;
}

When I compile this program with g++3.4.3 as
g++ -std=c++98 -pedantic -Wall -Wextra x.cpp

I get the following compilation error:
x.cpp: In function `int main()':
x.cpp:35: error: no matching function for call to `fn(<unknown type>)'

Why do I get this compilation error ? Kindly explan. Please help to
fix this error. I do not get the compilation error, if I have the
function template 'fn()' as follows:
template<class T>
inline void fn(void (T::*memfnPtr)() const)
{
return;
}

Note that in the above modified version of 'fn()', I have added
'const' to the parameter. Why don't I get the compilation error
for this version but I do get for the earlier version ?

Thanks
V.Subramanian

 

[Victor Bazarov]

The following quesion is NOT a HOMEWORK problem.

Consider the following x.cpp:

#include<cstdlib>
#include<iostream>

using namespace std;

template<class T>
inline void fn(void (T::*memfnPtr)())
{
return;
}

class Test
{
public:
void member();
void member() const;
};

inline void Test::member(void)
{
cout<< "Test::member() called"<< endl;

return;
}

inline void Test::member(void) const
{
cout<< "Test::member() const called"<< endl;

return;
}

int main()
{
fn(&Test::member);

return EXIT_SUCCESS;
}

When I compile this program with g++3.4.3 as
g++ -std=c++98 -pedantic -Wall -Wextra x.cpp

I get the following compilation error:
x.cpp: In function `int main()':
x.cpp:35: error: no matching function for call to `fn(<unknown type>)'

Why do I get this compilation error ? Kindly explan. Please help to
fix this error. I do not get the compilation error, if I have the
function template 'fn()' as follows:
template<class T>
inline void fn(void (T::*memfnPtr)() const)
{
return;
}

Note that in the above modified version of 'fn()', I have added
'const' to the parameter. Why don't I get the compilation error
for this version but I do get for the earlier version ?

Most likely a bug in the compiler. Comeau C++ accepts the code without
a hiccup. So does Visual C++ 2008 (it points out that the argument of
the template 'fn' is unused, but it's a warning).

V

 

[mingze zhang]

Most likely a bug in the compiler.  Comeau C++ accepts the code without
a hiccup.  So does Visual C++ 2008 (it points out that the argument of
the template 'fn' is unused, but it's a warning).

V

Additional info: On g++ 4.4.3-4ubuntu5, the above code is fine too.

3.4.3 was released in November 4, 2004, probably it's too old to
differentiate the pointers to member functions overloaded by const?