Error C4439 'main' : function definition with a managed type in the signature must ha

**Banfa** · Jul 20 '10, 09:10 AM

Are you are are you not using .NET?

Does your project require it?

**Banfa** · Jul 21 '10, 12:21 AM

I have made a GUI using the Windows Form Application. On button clicks on the GUI the program sends messages via USB to a connected device. Also one of the button connects this device to Skype and interacts with it.

Since I am using the windows Form application I THINK (in the limited knowledge I have) that I would need a .Net environment to run the .exe file.

Please feel free to correct me if I am wrong.

No you do not need to use .NET to create Windows programs, you can call the WIN32 API directly.

I asked because your errors look like they may be being produced by a clash between .NET and non-.NET code.

However I am not an expert on that.

**Soorali** · Jul 21 '10, 12:34 AM

Hi Banfa,

Thanks for your response.

I have checked my project properties and am using the Win32 API.

Do you have any idea what could be causing this??

Regards,
Soorali

**Banfa** · Jul 21 '10, 08:34 AM

This

Code:

int __clrcall main(array<System::String ^> ^args)

is the managed code version of main, you should be using either

Code:

int main(int argc, char* argp[])

Or its Microsoft equivalent wide character version

Code:

int wmain( int argc , wchar_t *argv[]);

Or its Microsoft equivalent that automatically selects the single or wide character version

Code:

int _tmain(int argc, _TCHAR* argv[])

Using this prototype automatically selects the correct version of the previous 2.

Another alternative is

Code:

int WINAPI _tWinMain(HINSTANCE hInstance,
    HINSTANCE hPrevInstance,
    LPTSTR lpCmdLine,
    int nCmdShow)

This is the Windows entry point again the _t indicating that it automatically switches between single byte and multibyte characters. You should be using this if you are compiling as a Windows application as opposed to a console application.

**johny10151981** · Jul 21 '10, 11:48 AM

Hi,
This answer is obsolet now :)
cause I didnt notice Banfa described it well :)

Hi,
Your main function definition says, its not a GUI program
you are doing console application.
in console application you can define main like this

Code:

int main(int argc, char *argv[]);

But if this is a graphical user interface the definition is different

Code:

int __stdcall WinMain(HINSTANCE hPrevInstance,
                     LPTSTR    lpCmdLine,
                     int       nCmdShow)

or

Code:

int APIENTRY _tWinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPTSTR    lpCmdLine,
                     int       nCmdShow)

infact APIENTRY,WINAPI and __stdcall are all same

Code:

#define WINAPI __stdcall 
#define APIENTRY WINAPI

and

Code:

#define _tWinMain wWinMain

wWinMain is widecharcter version of WinMain

Let me know if my above information is wrong

Johny

**Soorali** · Jul 22 '10, 06:17 AM

Hi Banfa/ Johny,

Thank you for replying to my post.

It finally works!!!

This is what I did:

Changed the call to the main routine to :

int __clrcall main(array<Syst em::String ^> ^args)

It did not seem to like the _stdcall before main.

Got the usual 12 Link errors with the __clrcall. Then realised the lib files were missing from the Additional Dependancies from the Project Properties. Included those and after a few hiccups it finally works!!!

One thing I am a bit confused by....in the Project Properties it says I am using the .Net Framework but on a Win32 platform....is that why I need the __clrcall before the main???

Let me know your thoughts please.

Cheers
Soorali

Error C4439 'main' : function definition with a managed type in the signature must ha

Error C4439 'main' : function definition with a managed type in the signature must ha

Comment

Comment

Comment

Comment

Comment

Comment