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Template methods - avoiding instantiation, declaration andimplementation in header file

P: n/a
Hi ,

Since, i did not want to write all instantiations in Source file of
all template methods for various different datatypes that my client
might use, Instead, i choose to write implementation of template
methods along with their declarations in the header file. Well, there
are also other files in the project, which include this header file as
well, which all gets compiled, linked and tested well.

#ifndef __ATT_H__
#define __ATT_H__
namespace TESTSPACE
{

class Att : public Abs
{

public:
template<class T>
unsigned long read(T& start, unsigned long count=0)
{
//Implementation written here
}
unsigned long read(std::back_insert_iterator< vector<std::string&
start, unsigned long count=0)
{
//Implementation written here
}
template<class T>
unsigned long write(T& start, T& stop)
{
//Implementation written here
}
unsigned long write(vector <std::string>::iterator& start, vector
<std::string>::iterator& stop)
{
//Implementation written here
}

};

#endif


However, to keep the header file look more reader friendly with just
declarations and moving all the implementation towards the end of the
header file, however generates me errors as

"error C2373: 'TESTSPACE::Att::read' : redefinition; different type
modifiers."
What am i missing here ? The template functions are basically
overloaded template methods, then why does the compiler throw error
for the above code ?

#ifndef __ATT_H__
#define __ATT_H__
namespace TESTSPACE
{

class Att : public Abs
{

public:
template<class T>
unsigned long read(T& start, unsigned long count=0);
unsigned long read(std::back_insert_iterator< vector<std::string&
start, unsigned long count=0);
template<class T>
unsigned long write(T& start, T& stop);
unsigned long write(vector <std::string>::iterator& start, vector
<std::string>::iterator& stop);

};

//All implementations done here temporarily
//Move below code to a separate "impl.h" file later
template<class T>
unsigned long Att::read(T& start, unsigned long count)
{
//Implementation written here
}
unsigned long Att::read(std::back_insert_iterator<
vector<std::string& start, unsigned long count)
{
//Implementation written here
}
template<class T>
unsigned long Att::write(T& start, T& stop)
{
//Implementation written here
}
unsigned long Att::write(vector <std::string>::iterator& start,
vector <std::string>::iterator& stop)
{
//Implementation written here
}

#endif

What am i missing here ? The template functions are basically
overloaded methods, then why does the compiler throw error for the
above code ?

Thanks
Jun 27 '08 #1
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