cpp File not compiling with cl, but compiles just fine inside Visual Studio

Question

I'm having an issue where the following code can't be compiled using CL (VS CMD). Instead of Compiling, it gives me Error LN2019. Compiling the same Code inside VS, compiles without errors.

#include <windows.h>

LRESULT CALLBACK
MainWindowCallback( HWND   Window,
                    UINT   Message,
                    WPARAM WParam,
                    LPARAM LParam)
{
    LRESULT Result = 0;

    switch(Message)
    {
        case WM_SIZE:
        {
            OutputDebugStringA("WM_SIZE\n");
        } break;

        case WM_DESTROY:
        {
            OutputDebugStringA("WM_DESTROY\n");
        } break;

        case WM_CLOSE:
        {
            OutputDebugStringA("WM_CLOSE\n");
        } break;

        case WM_ACTIVATEAPP:
        {
            OutputDebugStringA("WM_ACTIVATEAPP\n");
        } break;

        default:
        {
            // OutputDebugSTringA("default\n")
            Result = DefWindowProc(Window, Message, WParam, LParam);
        } break;
    }

    return(Result);
}

int CALLBACK
WinMain(HINSTANCE Instance,
        HINSTANCE PrevInstance,
        LPSTR     CommandLine,
        int       ShowCode)
{
    WNDCLASS WindowClass = {};

    WindowClass.style = CS_OWNDC|CS_HREDRAW|CS_VREDRAW;
    WindowClass.lpfnWndProc = MainWindowCallback;
    WindowClass.hInstance = Instance;
    // WindowClass.hIcon;
    WindowClass.lpszClassName = "FooWindowClass";

    return(0);
}

I tracked down the issue to Line 36:

Result = DefWindowProc(Window, Message, WParam, LParam);

When i comment this line out, the file compiles just fine. The cl command used to Compile is also pretty standard:

cl -Zi Foo.cpp

Is there some cl parameter i missed?

From the prefix `LN`, I'm guessing this is a linker error: where is `DefWindowProc` defined? — R_Kapp, Jan 11 '16 at 15:49
You are missing a lot of switches that VisualStudio passes to cl. One of the project properties page(s) shows the generated command line. — Richard Critten, Jan 11 '16 at 15:55
If you receive an error, post the **entire** error message, unmodified. — IInspectable, Jan 12 '16 at 01:09

score 0 · Accepted Answer · answered Jan 11 '16 at 15:52

0

You must link with user32.lib:

cl Foo.cpp user32.lib

answered Jan 11 '16 at 15:52

mikedu95

1,725
2
12
24

Yes, this did it. Figured it would be a parameter like that. Any idea why it wouldn't automatically include user32.lib when using cl? Unlike in VS itself? – kazaamjt Jan 11 '16 at 15:57
@kazaamjt: Visual Studio doesn't automatically include any arguments to CL either. It uses those **you** specified in the project settings. – IInspectable Jan 12 '16 at 01:08

score -1 · Answer 2 · edited May 23 '17 at 10:28

-1

Error Error LN2019 is not having a "main" (you seem to have named it WinMain).

See also: error LNK2019: unresolved external symbol _main referenced in function ___tmainCRTStartup

edited May 23 '17 at 10:28

Community

1
1

answered Jan 11 '16 at 15:51

John Hascall

9,176
6
48
72

cpp File not compiling with cl, but compiles just fine inside Visual Studio

2 Answers2