Create a window (Windows API)

main.c

#ifndef UNICODE
#define UNICODE
#endif 

#include <stdio.h>

#define WIN32_LEAN_AND_MEAN
#include <Windows.h>

// types
typedef unsigned char u8;
typedef unsigned short u16;
typedef unsigned int u32;
typedef unsigned long long u64;

typedef signed char s8;
typedef signed short s16;
typedef signed int s32;
typedef signed long long s64;

LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam);

int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PWSTR pCmdLine, int nCmdShow)
{

    // Register the window class.
    const wchar_t CLASS_NAME[]  = L"Sample Window Class";

    WNDCLASS wc = {0};

    wc.lpfnWndProc   = WindowProc;
    wc.hInstance     = hInstance;
    wc.lpszClassName = CLASS_NAME;

    RegisterClass(&wc);

    // Create the window.

    HWND hwnd = CreateWindowEx(
            0,                              // Optional window styles.
            CLASS_NAME,                     // Window class
            L"Learn to Program Windows",    // Window text
            WS_OVERLAPPEDWINDOW,            // Window style

            // Size and position
            CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,

            NULL,       // Parent window    
            NULL,       // Menu
            hInstance,  // Instance handle
            NULL        // Additional application data
            );

    if (hwnd == NULL) {
        return 0;
    }

    ShowWindow(hwnd, nCmdShow);

    // Run the message loop.

    MSG msg = {0};
    while (GetMessage(&msg, NULL, 0, 0) > 0)
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return 0;
}

LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    static HPEN hpen;
    static HBRUSH hbr;
    static HBRUSH hbr_bg;

    switch (uMsg)
    {
        case WM_CREATE:
            // hpen = (HPEN) GetStockObject(BLACK_PEN);
            hpen = (HPEN) GetStockObject(NULL_PEN);
            hbr = (HBRUSH) GetStockObject(GRAY_BRUSH);
            // hbr_bg = CreateSolidBrush(RGB(255, 255, 255));
            hbr_bg = CreateSolidBrush(RGB(0, 0, 0));
            return 0;

        case WM_DESTROY:
            DeleteObject(hpen);
            DeleteObject(hbr);
            DeleteObject(hbr_bg);
            PostQuitMessage(0);
            return 0;

        case WM_PAINT:
            {
                RECT rect;
                GetClientRect(hwnd, &rect);

                PAINTSTRUCT ps;
                HDC hdc = BeginPaint(hwnd, &ps);

                SaveDC(hdc);
                SelectObject(hdc, hpen);
                SelectObject(hdc, hbr);

                // FillRect(hdc, &ps.rcPaint, (HBRUSH) (COLOR_WINDOW+4));
                // FillRect(hdc, &ps.rcPaint, (HBRUSH) (COLOR_BLACK));
                FillRect(hdc, &ps.rcPaint, hbr_bg);

                // All painting occurs here, between BeginPaint and EndPaint.
                Rectangle(hdc,
                        0, 0,
                        10, 10);
                // Rectangle(hdc,
                //         0, 20,
                //         20, 20);
                // Rectangle(hdc,
                //         rect.right / 4 - 10, rect.bottom / 4 - 10,
                //         rect.right / 4 + 10, rect.bottom / 4 + 10);

                RestoreDC(hdc, -1);

                EndPaint(hwnd, &ps);
            }
            return 0;
    }
    return DefWindowProcW(hwnd, uMsg, wParam, lParam);
}

make.sh

#!/bin/sh

# ./make.sh [debug, release]

if [ $# -lt 1 ]; then
  echo "need a parameter [debug, release]"
  exit 0
fi

if [ $1 = "debug" ]; then
  OPTIMIZATION="-O0"
  HIDE_CONSOLE=""
elif [ $1 = "release" ]; then 
  OPTIMIZATION="-O2"
  HIDE_CONSOLE="-mwindows"
else
  echo "unknown parameter: $1"
  exit 0
fi

# clear

C_FLAGS="-std=c99 ${OPTIMIZATION} -Wall -Wextra -pedantic -Wno-unused-parameter -Wno-missing-field-initializers"

COMPILER='gcc'

COMMAND="${COMPILER} ${C_FLAGS} main.c -o main.exe -Wl,-subsystem,windows -municode -lgdi32"

${COMMAND}