C++からwin32apiでWinMainを使うmeson.buildを書いてみる

WinMainを使う場合、/SUBSYSTEM:WINDOWSを指定する。

問題は、mesonが勝手に/SUBSYSTEM:CONSOLEをつけてしまうので、エントリポイントがmainなのかWinMainなのかわからなくなりエラーが出る。

これを回避するために、 gui_app: true を指定する。

project('myapp', 'cpp') 
 
cpp = meson.get_compiler('cpp') 
 
executable('myapp', 'main.cpp',  
 
  gui_app: true,    # WinMainを使うときはこれが必要 
 
  cpp_args: [ 
    '/D_WINDOWS' 
  ], 
     
  link_args: [ 
    '/SUBSYSTEM:WINDOWS'  # WinMainを使うときはこれが必要 
  ] 
 
) 

ビルド

meson setup build

meson compile -C build

の順で実行する。

	
(mesonenv) C:\Users\myuser\source\repos\win32>meson setup build 
Directory already configured. 
 
Just run your build command (e.g. ninja) and Meson will regenerate as necessary. 
If ninja fails, run "ninja reconfigure" or "meson setup --reconfigure" 
to force Meson to regenerate. 
 
If build failures persist, run "meson setup --wipe" to rebuild from scratch 
using the same options as passed when configuring the build. 
To change option values, run "meson configure" instead. 
 
(mesonenv) C:\Users\myuser\source\repos\win32>meson compile -C build 
Activating VS 17.5.4 
INFO: automatically activated MSVC compiler environment 
INFO: autodetecting backend as ninja 
INFO: calculating backend command to run: C:\Users\myuser\anaconda3\envs\mesonenv\Library\bin\ninja.EXE -C C:/Users/szl/source/repos/win32/build 
ninja: Entering directory `C:/Users/myuser/source/repos/win32/build' 
[0/1] Regenerating build files. 
The Meson build system 
Version: 1.0.1 
Source dir: C:\Users\myuser\source\repos\win32 
Build dir: C:\Users\myuser\source\repos\win32\build 
Build type: native build 
Project name: myapp 
Project version: undefined 
C++ compiler for the host machine: cl (msvc 19.35.32217.1 "Microsoft(R) C/C++ Optimizing Compiler Version 19.35.32217.1 for x64") 
C++ linker for the host machine: link link 14.35.32217.1 
Host machine cpu family: x86_64 
Host machine cpu: x86_64 
Build targets in project: 1 
 
Found ninja-1.10.2 at C:\Users\myuser\anaconda3\envs\mesonenv\Library\bin\ninja.EXE 
Cleaning... 0 files. 
[1/1] Linking target myapp.exe 

サンプルコード main.cpp

#include<windows.h>

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wp, LPARAM lp) {
  HDC hdc;
  switch (msg) {
  case WM_DESTROY:
    PostQuitMessage(0);
    return 0;
  }
  return DefWindowProc(hwnd, msg, wp, lp);
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
  PSTR lpCmdLine, int nCmdShow) {
  HWND hwnd;
  WNDCLASS winc;
  MSG msg;

  winc.style = CS_HREDRAW | CS_VREDRAW;
  winc.lpfnWndProc = WndProc;
  winc.cbClsExtra = winc.cbWndExtra = 0;
  winc.hInstance = hInstance;
  winc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
  winc.hCursor = LoadCursor(NULL, IDC_ARROW);
  winc.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
  winc.lpszMenuName = NULL;
  winc.lpszClassName = TEXT("SZL-WIN");

  if (!RegisterClass(&winc)) return 0;

  hwnd = CreateWindow(
    TEXT("SZL-WIN"), TEXT("test"),
    WS_OVERLAPPEDWINDOW | WS_VISIBLE,
    CW_USEDEFAULT, CW_USEDEFAULT,
    CW_USEDEFAULT, CW_USEDEFAULT,
    NULL, NULL,
    hInstance, NULL
  );

  if (hwnd == NULL) return 0;

  while (GetMessage(&msg, NULL, 0, 0)) DispatchMessage(&msg);
  return msg.wParam;
}