Rust+windows-rs,win32apiでCreateWindowしてみる

use windows::Win32::System::LibraryLoader::GetModuleHandleA;
use std::env;
use windows::Win32::System::Threading::{GetStartupInfoW, STARTUPINFOW};

// mod ファイル名
mod winmain;
// use 関数名（など）
use winmain::WinMain;

// Rustのwindows-rsからウィンドウズアプリケーションをビルドする時には、
// WinWain ではなくmainをエントリポイントとする。

fn main()-> windows::core::Result<()>  {

    let hInstance:windows::Win32::Foundation::HINSTANCE;
    unsafe{
        // https://github.com/microsoft/windows-samples-rs/blob/master/create_window/src/main.rs
        hInstance = windows::Win32::System::LibraryLoader::GetModuleHandleA(None).unwrap();
    }

    // https://doc.rust-jp.rs/book-ja/ch12-01-accepting-command-line-arguments.html
    let args: Vec<String> = env::args().collect();


    // https://stackoverflow.com/questions/68322072/how-to-get-args-from-winmain-or-wwinmain-in-rust
    let mut si = windows::Win32::System::Threading::STARTUPINFOW {
        cb: std::mem::size_of::<windows::Win32::System::Threading::STARTUPINFOW>() as u32,
        ..Default::default()
    };
    unsafe { 
        windows::Win32::System::Threading::GetStartupInfoW(&mut si) 
    };
    let cmd_show = si.wShowWindow as i32;

    ////////////////////////////////////////////////////////////////////////////////////
    // 自作WinMainを呼び出す 
    WinMain(
        hInstance,
        windows::Win32::Foundation::HINSTANCE(0),
        args,
        cmd_show
    );


    Ok(())

}

use windows::{
    core::*, Win32::Foundation::*, Win32::Graphics::Gdi::ValidateRect,
    Win32::System::LibraryLoader::GetModuleHandleA, Win32::UI::WindowsAndMessaging::*,
};

extern "system" fn wndproc(window: HWND, message: u32, wparam: WPARAM, lparam: LPARAM) -> LRESULT {
    unsafe {

        
        let rectnullptr: ::core::option::Option<*const windows::Win32::Foundation::RECT> = None;

        match message as u32 {
            WM_PAINT => {
                println!("WM_PAINT");
                ValidateRect(window, rectnullptr);
                LRESULT(0)
            }
            WM_DESTROY => {
                println!("WM_DESTROY");
                PostQuitMessage(0);
                LRESULT(0)
            }
            _ => DefWindowProcA(window, message, wparam, lparam),
        }
    }
}

/// 自作 WinMain
pub fn WinMain(
        hInstance : windows::Win32::Foundation::HINSTANCE, 
        hPrevInstance : windows::Win32::Foundation::HINSTANCE, 
        lpCmdLine:Vec<String>, 
        nCmdShow:i32
    )->i32{

    unsafe{
        let _hCursor = LoadCursorW(None,IDC_ARROW).unwrap();
        let _hInstance = hInstance;
        let _lpszClassName = PCSTR::from_raw("MY_NEW_WINDOW\0".as_ptr());
        let _style = CS_HREDRAW | CS_VREDRAW;

        // https://microsoft.github.io/windows-docs-rs/doc/windows/Win32/UI/WindowsAndMessaging/struct.WNDCLASSA.html
        let wc=windows::Win32::UI::WindowsAndMessaging::WNDCLASSA{
            hCursor :_hCursor,
            hInstance: _hInstance,
            lpszClassName: _lpszClassName,
            style: _style,
            lpfnWndProc: Some(wndproc),
            ..Default::default()
        };

        let atom = RegisterClassA(&wc);
        debug_assert!(atom != 0);


        let nullptr: ::core::option::Option<*const ::core::ffi::c_void> = None;

        CreateWindowExA(
            Default::default(),
            _lpszClassName,
            PCSTR::from_raw("This is a sample window\0".as_ptr()),
            WS_OVERLAPPEDWINDOW | WS_VISIBLE,
            CW_USEDEFAULT,
            CW_USEDEFAULT,
            CW_USEDEFAULT,
            CW_USEDEFAULT,
            None,
            None,
            _hInstance,
            nullptr,
        );


        let mut message = MSG::default();

        while GetMessageA(&mut message, HWND(0), 0, 0).into() {
            DispatchMessageA(&mut message);
        }
    }
    return 0;


}

PCSTR::from_raw("This is a sample window\0".as_ptr()),

let _hCursor = LoadCursorW(None,IDC_ARROW).unwrap();

let nullptr: ::core::option::Option<*const ::core::ffi::c_void> = None;