Find how to get this error

[LB]

I have another challenge: write code that compiles perfectly but then gives this linker error:

Main.obj : fatal error LNK1179: invalid or corrupt file: duplicate COMDAT '_main'

Hint: Use main twice differently. Note that you will get a compiler error if you try to overload main. Removing the second or first use of main should end up calling main twice (meaning it compiles and links, and runs)

[ne555]

Which "compiler" are you using?

[LB]

The Visual C++ 2008 Express Edition compiler. I'm not sure whether the compiler matters, just a similar error message should suffice.

[eidge]

In C::B if I call main inside main it compiles and runs, but crashes..

[zwA4jE8b]

Got me...
but thats not too hard to do.
I can call main in main and get a stack overflow but thats about it.

[LB]

Haha, infinite recursion is not considered a compile error unless you have infinite recursion templates. This challenge does not involve recursion ;)

[zwA4jE8b]

1>forum-help.obj : error LNK2005: _main already defined in f.obj
1>C:\Visual Studio 2010\C++\forum-help\Debug\forum-help.exe : fatal error LNK1169: one or more multiply defined symbols found

.. getting closer only 10 error messages away, lol

EDIT: Don't know enough about linking

[LB]

Neither do I, I just wrote some code to see what would happen and I got the linker error ;)
Hint: I only used one .cpp file and I only included <iostream> (it would still work without including iostream)

[zb0S216C]

All I've managed to get was an access violation when returning from main (all I defined was a single integer (non-allocating)). LOL.

_Wazzak

[LB]

I think I'll post the solution:

template<typename T>
int main()
{
	cout << "Hello, World!" << endl;

	cin.sync();
	cin.ignore();
}

int RunMainFunction = main<void>() + main<unsigned>();

If you comment out one of the two calls to main for the global variable, it will compile and link fine.

[ne555]

error: cannot declare '::main' to be a template
error: ISO C++ forbids taking address of function '::main'

[LB]

Huh, what compiler are you using? It compiles perfectly in Visual C++ 2008 Express Edition.

[Athar]

That's not valid C++ since you cannot overload the main function.
Apparently VC++ fails to recognize this, so it leaves it to the linker to pick up the pieces.