Template class organization

[Zaei]

No, the problem comes when you actually compile the C++, instead of including it into a header. At that point, the code is already compiled into an obj, but when you try to instantiate, for instance A<int>, you get unresolved external symbols, because the actual implmentations of those functions never get compiled. I eventually changed the .cpp extensions to .inc, and included into the header, and everything works fine.

Z.

[Technocrat]

This is SO FREAKY Zaei I was just going to ask that very same question!!!

So if any one knows how to do this I would like to know too.

All the examples I have found have all the template code in the header.

[Technocrat]

I found the answer
Templates HAVE to be in the header, unless you have .cpp local templates

like:

template<class T> T Test(T &a, T &b)
{
T Temp = a;
a = b;
b = Temp;
return Temp;
}

void Test2()
{
int p, j, z;
p = 4;
j = 7;
z = Test<int>(p,j);
}

int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, LPSTR lpCmdLine, int nCmdShow)
{
Test2();
....


Here is where I found the answer
http://www.codeguru.com/cgi-bin/bbs/wt/showpost.pl?Board=CPP&Number=2248&page=&view=&sb=

[kedaman]

you are absolutely right, I never came to that situation (i generally always compile them altogether in one file)
The compiler will find it if you specify

A<int>::A()
{

}

but that's hardly usefull :/
might be an ugly solution but including a macro which with you can declare which instantces you need (and it will expand to specifications with the accurate contents)
but i'd say put them all in the same file.

[kedaman]

well obviously the specific implementation can be in the cpp file, as long as the linker finds it.

[Zaei]

Kind of a pain, but it makes sense.

Z.

[kedaman]

And one thing, it can't inline can it?

[Zaei]

I dont think templates can be inline, but Im not sure, as i dot use them very often =).

Z.

[kedaman]

LOL, I would never even use templates if they wouldn't inline :D well, maybe, but that would suck insaneously!
templates advocates inlining!

[Zaei]

Mah bad =). Like i said, I dont use them very much.

Z.

[kedaman]

you should! you'll learn that most of the things you do, you only need to do once :)

[parksie]

Originally posted by kedaman
you should! you'll learn that most of the things you do, you only need to do once :) Such as talking to Kedaman...you only need to say one thing and he'll provide you with endless bits of information :D