VC++ 2010 Error

[Arpan Das]

1>------ Build started: Project: Test project 1, Configuration: Debug Win32 ------
1>LINK : error LNK2001: unresolved external symbol _mainCRTStartup
1>C:\Users\admin\documents\visual studio 2010\Projects\Test project 1\Debug\Test project 1.exe : fatal error LNK1120: 1 unresolved externals
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========





This is my build report.
its a very simple code to print hello world in an empty page , no precompiler header. what am i doing wrong?

[Salem]

Do you have a winMain () ?

In which case, you have a GUI program, but you're using a console project.

[smokeyangel]

^^ what Salem said.

I'm guessing you want a console app -- you'll have to check your project type and make sure main() is defined.

For pretty much everything, I use project type Visual C++/Win32/Win32 Console Application -- empty project, no precompiled headers.

If you're trying to do a GUI program you should give some thought to how you want to do it, I've found .NET easier to work with than MFC. Either way, if you want to do that you probably shouldn't select 'empty project' -- MSVC generates a few files which you can fill in. That should include the right definition of main() or winMain()

[rags_to_riches]

Visual C++ Tutorials, Library, and More on MSDN

[Arpan Das]

Its console application , and empty in Win32 , with void main().
No Gui stuff.

[iMalc]

Well void main would be one problem. main must always return int.

[smokeyangel]

It's odd actually... mainCRTStartup is the library function that calls main().

Your linker error was
error LNK2001: unresolved external symbol _mainCRTStartup

I just tested the behaviour on my machine - a different error message is emitted when main is improperly specified.

It seems like the linker is not pulling in all the libraries that it should. That feels like an installation problem -- maybe you didn't reboot when it asked you to? I know it does do some final environment setup after reboot.

I'm actually using MSVC2008 but I don't think that will make any difference.

Examining the linker's verbose output I see (in my successful build):
Searching C:\Program Files\Microsoft Visual Studio 9.0\VC\lib\MSVCRTD.lib:
Found _mainCRTStartup
Loaded MSVCRTD.lib(crtexe.obj)

I've attached my successful build output (rename it to .html, apparently I can't attach html files). You could enable verbose linker output in MSVC (Project->Properties->Linker Show progress=display all progress messages) then have a look at your output build log file and see where it's going wrong. I bet it's not scanning MSVCRTD.lib.

[Arpan Das]

I went through the Win32 Wizard with an empty project , no precompiler. And did not get the link error. accepts the void main , but is not accepting the iostream.h library for some reason unknown to me.

[AndrewHunter]

#include <iostream>
...
using namespace std;

Read why void main is wrong.

MSVC++ accepts void main but it changes it to int main() during the compile phase to maintain C99 compliance. It just allows YOU NOT TO BE

EDIT: If for no other reason then use int main so Salem won't obliterate you. Hint: I think it is a pet peeve.

[smokeyangel]

There's no iostream.h header on MSVC. You need to #include <iostream> (no .h).

[rags_to_riches]

As he was told by you in his other thread. If you really want to learn, Arpen Das, you need to pay careful attention to all the advice you are receiving.

accepts the void main

As *I* said in your other thread, while Microsoft's compiler will accept void main(), it is still wrong, as pointed out above. MS is simply hiding from you your failure to follow the standard and converting it to int main() silently. That's fine if you only ever write code in MSVC, but as soon as you try to compile in a stricter or more standards-conforming compiler, you're going to end up with errors.

[Arpan Das]

Hey , yes I started reading now , got accelerated c++ , going through it now. Will pick it up now I guess , thanks

[Elysia]

I went through the Win32 Wizard with an empty project , no precompiler. And did not get the link error. accepts the void main , but is not accepting the iostream.h library for some reason unknown to me.

Do not create Win32 projects. Use console projects.