c++ - 当用于其 windproc 内部的参数时，HWND 地址发生变化

Question

我试图制作一个函数 createscalingwindow 调用 CreateWindowEx 并将 CreateWindowEx 中使用的 HWND 地址写入一个 vector ，然后通过它的初始大小和位置值。

我制作的另一个名为 scalewindowsize 的函数应该使用两个给定的窗口并将一个窗口的大小与另一个窗口缩放，但目前我什至无法匹配某些 HWND 的地址，因为在某些情况下条件下传递给 scalewindowsize 的 HWND 地址将与初始化时的地址完全不同。只有当我从窗口过程调用 scalewindowsize 时，在窗口过程的参数中使用与 scalewindowsize 的参数中使用的 HWND 相同的 HWND，才会发生这种情况。下面是相关代码:

#include <windows.h>
#include <stdio.h>
#include <winsock.h>
#include <vector>
#define ID_1 1000
#define ID_2 1001
#define ID_3 1002
HWND mainwin;  
HWND lobbywin;
int zero = 0;
char MENU1;
std::vector<intptr_t> sizevalues;
LRESULT CALLBACK mainproc (HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK lobbyproc (HWND, UINT, WPARAM, LPARAM);
char mainclassname[] = "main";
char lobbyclassname[] = "lobby";

void createscalingwindow(HWND &cswpara0,DWORD cswpara1,const CHAR* cswpara2,
const CHAR* cswpara3,DWORD cswpara4,int cswpara5,int cswpara6,int cswpara7,
int cswpara8,HWND cswpara9,HMENU cswpara10,HINSTANCE cswpara11,LPVOID cswpara12)
{
  cswpara0 = CreateWindowEx (cswpara1, cswpara2, cswpara3, cswpara4,cswpara5,
  cswpara6,cswpara7,cswpara8,cswpara9,cswpara10,cswpara11,cswpara12);
  char buffer[100];
  sizevalues.push_back((intptr_t)&cswpara0);
  snprintf (buffer, 20,"%d", sizevalues[zero]);
  MessageBox (NULL, buffer, "initialized", NULL);
  zero = (zero + 1);
  return;
}         

void scalewindowsize (HWND &ownerwin, const CHAR* tryz)
{
  char buffer[100];
  int checknumber = 0; 
  while (checknumber < sizevalues.size())
  {
    int compare = sizevalues[checknumber];
    if (sizevalues[checknumber] == (intptr_t)&ownerwin)
    {
      snprintf (buffer, 100,"%d", (intptr_t)&ownerwin);
      MessageBox (NULL, buffer, "value found", NULL);
      break;
    }
    else 
    {
      snprintf (buffer, 100,"%d", (intptr_t)&ownerwin);
      MessageBox (NULL, buffer, tryz, NULL);
      snprintf (buffer, 100,"%d", sizevalues[checknumber]);
      checknumber = (checknumber + 1);
      MessageBox (NULL, buffer, "fail currentcheck", NULL);
    }
  }
  return;
}

int WINAPI WinMain (HINSTANCE hThisInstance, HINSTANCE hPrevInstance,
LPSTR lpszArgument, int nCmdShow)
{
  MSG messages; 
  WNDCLASSEX mainwinclass;
  mainwinclass.hInstance = hThisInstance;
  mainwinclass.lpszClassName = mainclassname;
  mainwinclass.lpfnWndProc = mainproc;
  mainwinclass.style = CS_DBLCLKS;
  mainwinclass.cbSize = sizeof (WNDCLASSEX);
  mainwinclass.hIcon = LoadIcon (NULL, IDI_APPLICATION);
  mainwinclass.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
  mainwinclass.hCursor = LoadCursor (NULL, IDC_ARROW);
  mainwinclass.lpszMenuName = NULL;
  mainwinclass.cbClsExtra = 0;
  mainwinclass.cbWndExtra = 0;
  mainwinclass.hbrBackground = (HBRUSH) COLOR_BACKGROUND;
  if (!RegisterClassEx (&mainwinclass))
   return 0;

  WNDCLASSEX lobbywinclass;        
  lobbywinclass.hInstance = hThisInstance;
  lobbywinclass.lpszClassName = lobbyclassname;
  lobbywinclass.lpfnWndProc = lobbyproc;    
  lobbywinclass.style = CS_DBLCLKS;                
  lobbywinclass.cbSize = sizeof (WNDCLASSEX);
  lobbywinclass.hIcon = LoadIcon (NULL, IDI_APPLICATION);
  lobbywinclass.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
  lobbywinclass.hCursor = LoadCursor (NULL, IDC_ARROW);
  lobbywinclass.lpszMenuName = NULL;                 
  lobbywinclass.cbClsExtra = 0;                     
  lobbywinclass.cbWndExtra = 0;                      
  lobbywinclass.hbrBackground = (HBRUSH) COLOR_BACKGROUND;


  if (!RegisterClassEx (&lobbywinclass))
   return 0;
  HMENU playmenu = CreateMenu();
  HMENU playmenulist = CreatePopupMenu();
  HMENU helpmenulist = CreatePopupMenu();
  AppendMenu(playmenulist, MF_STRING, ID_1, "Join game");
  AppendMenu(playmenulist, MF_STRING, ID_3, "Host game");
  AppendMenu(playmenulist, MF_STRING, ID_2, "Quit");
  InsertMenu(playmenu, 1, MF_POPUP|MF_BYPOSITION, (UINT_PTR)playmenulist, "Play");

  createscalingwindow(mainwin, 0, mainclassname, "mainwindow",
  WS_OVERLAPPED|WS_CAPTION|WS_THICKFRAME|WS_MINIMIZEBOX|WS_MAXIMIZEBOX|WS_SYSMENU, 
  CW_USEDEFAULT, CW_USEDEFAULT, 544, 375, NULL, playmenu, hThisInstance, NULL);
  ShowWindow (mainwin, nCmdShow);

  createscalingwindow(lobbywin, 0, lobbyclassname, "Lobby", WS_OVERLAPPEDWINDOW,
  CW_USEDEFAULT, CW_USEDEFAULT, 600, 425, NULL, NULL, hThisInstance, NULL);

  while (GetMessage (&messages, NULL, 0, 0))
  {
    TranslateMessage(&messages);
    DispatchMessage(&messages);
  }
  return messages.wParam;
}

LRESULT CALLBACK mainproc(HWND mainwin, UINT message, WPARAM wParam, LPARAM lParam)
{
  switch (message)         
  {
    case WM_SIZE:
    {
      scalewindowsize (mainwin, "mainwin");
      scalewindowsize (lobbywin, "lobbywin");
      break;
    }
    case WM_DESTROY:
    PostQuitMessage(0);
    break;
  } 
  switch (wParam)
  {
    case ID_3:
    EnableWindow (mainwin, false);
    ShowWindow (mainwin, false);
    ShowWindow (lobbywin, true);              
    break;
    default:  
    return DefWindowProc (mainwin, message, wParam, lParam); 
    break;
  }  
  return 0;
}    
LRESULT CALLBACK lobbyproc(HWND lobbywin, UINT message, WPARAM wParam, LPARAM lParam)
{
  switch (message)
  {
    case WM_SIZE:
    {
      scalewindowsize (mainwin, "mainwin");
      scalewindowsize (lobbywin, "lobbywin");
      break;
    }
    break;
  }
  switch (wParam)
  {
    case SC_CLOSE:
    {
      EnableWindow (mainwin, true);
      ShowWindow (mainwin, true);
      ShowWindow (lobbywin, false);
      EnableWindow (lobbywin, false);
      break;
    }
    default:
    return DefWindowProc (lobbywin, message, wParam, lParam);
    break;
  }
}

如果我运行这个程序，点击主机游戏，返回到主窗口并稍微调整它的大小(在 mainrpoc 中关闭 case WM_SIZE:)然后退出程序，我会按时间顺序得到以下消息框:

1[title: Initialized |text: 4231184]
2[title: mainwin |text: 2292968]
3[title: fail currentcheck |text: 4231184]
4[title: lobbywin |text: 4231188]
5[title: fail currentcheck |text: 4231184]
6[title: initialized |text: 4231188] (no more boxes until I click on host game)
7[title: value found: |text: 4231184]
8[title: lobbywin |text: 2292676]
9[title: fail currentcheck |text: 4231184]
10[title: lobbywin |text: 2292676]
11[title: fail currentcheck |text: 4231188] (no more boxes until I go back to the mainwindow and resize it slightly)
12[title: mainwin |text: 2291164]
13[title: fail currentcheck |text: 4231184]
14[title: mainwin |text: 2291164]
15[title: fail currentcheck |text: 4231188]
16[title: lobbywin |text: 4231188]
17[title: fail currentcheck |text: 4231184]
18[title: value found |text: 4231188]

我现在很困惑，我希望读到这篇文章的人能向我解释为什么地址会改变，在此先感谢您花时间阅读我的问题。

更新:对于正在阅读本文的任何人，除了 whoz craigs 的回答之外，我还想补充一点，即在 C++ 中调用全局变量而不是局部变量的方法是在变量之前添加::。

Answer 1

在两个窗口过程中，您都将参数 HWND 发送到 scalewindow；不是全局的。因此它们是不同的地址。名称解析使用“最接近”变量，在这两种情况下都是 HWND 参数，而不是您尝试使用的 HWND 全局变量。

例子:

LRESULT CALLBACK mainproc(HWND mainwin, UINT message, WPARAM wParam, LPARAM lParam)
{
  switch (message)         
  {
    case WM_SIZE:
    {
      scalewindowsize (mainwin, "mainwin");   // passes parameter mainwin by reference
      scalewindowsize (lobbywin, "lobbywin"); // passes global lobbywin by reference
      break;
    }

因此引用将具有不同的地址解析。另一个例子:

LRESULT CALLBACK lobbyproc(HWND lobbywin, UINT message, WPARAM wParam, LPARAM lParam)
{
  switch (message)
  {
    case WM_SIZE:
    {
      scalewindowsize (mainwin, "mainwin");   // passes global mainwin by reference
      scalewindowsize (lobbywin, "lobbywin"); // passes parameter lobbywin by reference
      break;
    }
    break;