Using template functions in Visual Studio C++ 6.0 - c++

Question

0Dear StackExchange Community,
I have for two hours tried to find the source of the problem but failed completly. Research=google search also did not provide any viable solutions. At least I was able to discover that under VS 6.0 one cannot split the declaration and implementation of a template function between header and .cpp-file.
Perhaps my approach is inherently flawed or it is VS 6.0 that is being particulary obnoxious this time.
Here is the test code I wrote.
#include "stdafx.h"
#include <string>
#include <iostream>
class TestClass{
public:
template<class T> inline bool isNull(T& inObject){
return 0; // edited because of the answer by Joachim Pileborg :)
// initial code was: return (inObject != NULL) ? 0:1;
}
};
using namespace std;
int main(int argc, char* argv[])
{
cout<<TestClass::isNull<string>("test");
return 0;
}
Running this code causes the following error:
fatal error C1001: INTERNER COMPILER- FEHLER
(Compiler-File "msc1.cpp", Row 1794)
Does anybody have an idea what I am doing wrong here?
P.S. : this time i really endevoured to ask the question as precisly as possible also providing a concrete example. Please let me know if there is anything else I should have added.
P.SS: I know that visual studio 6.0 ist pretty old but I am forced to use it at work. Running the same code with the a new compiler (at home) did not cause any errors. This is why I assume that the problem is mainly caused by the whims of VS 6.0.
Thanks in advance for you help !!
JD

Answer 1

Unless you define a custom casting operator that returns a pointer, an object instance can never be equal to NULL.

Answer 2

Apart from facts noted in comments and answers, internal compiler error happens in situation, when there's a bug in the compiler, that prevents it from compiling valid code.
Microsoft usually fixes these bugs in IDE hotfixes or in newer versions of compilers. Try to modify the structure of code such that it does the same thing, but looks differently - it's the only way to avoid the Internal Error problem.

Answer 3

There are several troubles in your code:
I rewrote it this way:
comparing the adress of the reference you're passing (you have edited your question but you wrote inObject==NULL in the body of your function and it couldn't compile either)
using const string& so has to be able to call TestClass::isNull<string>("test");
you must define your function as static if you want to call it the way you do
I'm not sure but the character '<' following your word template looked badly encoded in my IDE, so I replaced it with a commonplace <, it compiled better
it's a way of coding, but prefer using typename than class when defining templates
prefer using true and false instead of 1 and 0 ( you edited your question but you still return 0...)
=>
#include <string>
#include <iostream>
class TestClass{
public:
template<typename T>
static bool isNull(const T& inObject)
{
return (&inObject == NULL) ? true : false;
}
};
using namespace std;
int main(int argc, char* argv[])
{
cout<< TestClass::isNull<string>("test");
return 0;
}
Now it compiles fine.