简单的WinAPI应用程序有一个额外的控制台窗口

我复制粘贴了一个简单的c++ WinAPI应用程序的框架。它可以工作，但会创建一个额外的控制台窗口和GUI窗口。如何摆脱它?我正在使用MinGW中的GCC。

#include <windows.h>
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
static char sClassName[]  = "MyClass";
static HINSTANCE zhInstance = NULL;
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) {
        WNDCLASSEX WndClass;
        HWND hwnd;
        MSG Msg;
        zhInstance = hInstance;
        WndClass.cbSize        = sizeof(WNDCLASSEX);
        WndClass.style         = NULL;
        WndClass.lpfnWndProc   = WndProc;
        WndClass.cbClsExtra    = 0;
        WndClass.cbWndExtra    = 0;
        WndClass.hInstance     = zhInstance;
        WndClass.hIcon         = LoadIcon(NULL, IDI_APPLICATION);
        WndClass.hCursor       = LoadCursor(NULL, IDC_ARROW);
        WndClass.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
        WndClass.lpszMenuName  = NULL;
        WndClass.lpszClassName = sClassName;
        WndClass.hIconSm       = LoadIcon(NULL, IDI_APPLICATION);
        if(!RegisterClassEx(&WndClass)) {
                MessageBox(0, "Error Registering Class!", "Error!", MB_ICONSTOP | MB_OK);
                return 0;
        }
        hwnd = CreateWindowEx(WS_EX_STATICEDGE, sClassName, "db Tutorial", WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT,
                    320, 240, NULL, NULL, zhInstance, NULL);
        if(hwnd == NULL) {
                MessageBox(0, "Error Creating Window!", "Error!", MB_ICONSTOP | MB_OK);
                return 0;
        }
        ShowWindow(hwnd, nCmdShow);
        UpdateWindow(hwnd);
        while(GetMessage(&Msg, NULL, 0, 0)) {
                TranslateMessage(&Msg);
                DispatchMessage(&Msg);
        }
        return Msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam) {
        switch(Message) {
                case WM_CLOSE:
                        DestroyWindow(hwnd);
                        break;
                case WM_DESTROY:
                        PostQuitMessage(0);
                        break;
                default:
                        return DefWindowProc(hwnd, Message, wParam, lParam);
        }
        return 0;
}