Почему не работает моя функция обратного вызова Windows API?

Я написал код, который завершает egui.exe. Но моя функция обратного вызова не запускается после обработки сообщения WM_CLOSE. Зачем?

#include <iostream>
#include <windows.h>
#include <psapi.h>

using namespace std;

HWND ESETWindow = 0;    //Variable to store a handle to the main window
// of ESET Smart Security
HWND ConfirmationWindow = 0;    //Variable to store a handle to the
// confirmation dialog box that appears
// when a WM_CLOSE message is sent to
// the ESET window.
DWORD EGUIPID = 0;  //Variable to store the process identifier of egui.exe
BOOL CALLBACK EnumWindowsProc(HWND hwnd, LPARAM lParam);
VOID SendAsyncProc(HWND hwnd, UINT uMsg, ULONG_PTR dwData, LRESULT lResult);

int main()
{
cout << "Terminating ESET Smart Security..." << endl;

//Obtain an array of process identifiers including the PID of egui.exe
DWORD PIDs[1024]; //The array of process identifiers
DWORD bytesReturned;
if (!EnumProcesses(PIDs, sizeof(PIDs), &bytesReturned))
{
cerr << "Unable to enumerate the processes." << endl;
return 0;
}

//Enumerate the PIDs array to find the process of egui.exe.
DWORD nProcesses = bytesReturned / sizeof(DWORD);
for (DWORD i = 0;i < nProcesses;i++)
{
//Open the process to examine its executable file name.
HANDLE process = OpenProcess(PROCESS_QUERY_INFORMATION | PROCESS_VM_READ, FALSE, PIDs[i]);
//Create a buffer for the name of the executable file.
PSTR processName = (PSTR) VirtualAlloc((LPVOID) NULL, (DWORD) 10, MEM_COMMIT, PAGE_READWRITE);
//Get the name of the executable file name.
GetModuleBaseName(process, NULL, processName, 10);
//Check if the executable file name is egui.exe.
if (!lstrcmpi(processName, TEXT("egui.exe")))
{
EGUIPID = PIDs[i];
break;
}
VirtualFree(processName, 0, MEM_RELEASE);
CloseHandle(process);
}

//Display an error message if the process identifier of egui.exe
//could not be found.
if (!EGUIPID)
{
cerr << "Unable to find process identifier of egui.exe" << endl;
return 0;
}

//Enumerate the top-level windows to find the main window of
// ESET Smart Security and store a handle to that window in the
// ESETWindow variable.
EnumWindows(EnumWindowsProc, 0);
//Display an error message if the window could not be found.
if (!ESETWindow)
{
cerr << "Unable to find the primary window of ESET Smart Security." << endl;
return 0;
}

//Send a WM_CLOSE message to the main window of egui.exe in order
// to display a confirmation dialog box.
if (!SendMessageCallback(ESETWindow, WM_CLOSE, 0, 0, SendAsyncProc, 0))
{
cerr << "Unable to send a WM_CLOSE message to the primary window of ESET Smart Security." << endl;
return 0;
}

//Wait a second for the confirmation dialog box to appear...
Sleep(1000);
//Enumerate the windows again to find the confirmation dialog box.
EnumWindows(EnumWindowsProc, 1);
//Display an error message if the confirmation dialog box
// could not be found.
if (!ConfirmationWindow)
{
cerr << "Unable to find confirmation message." << endl;
cout << "If you have ESET NOD32, it is probably terminated successfully.";
cin.get();
}

//Find the Yes button in the confirmation dialog box and display
// an error message if failed.
HWND button = FindWindowEx(ConfirmationWindow, NULL, NULL, TEXT("&Yes"));
if (!button)
{
cerr << "Unable to find Yes button in the message box." << endl;
return 0;
}

//Activate the confirmation dialog box and simulate a mouse click
// on the Yes button.
SetActiveWindow(ConfirmationWindow);
SendMessage(button, BM_CLICK, 0, 0);
cout << "ESET Smart Security was successfully terminated!";

//Keep the program running until the user presses Enter
// in the console window.
cin.get();
return 0;
}

//If lParam is 0, the function below finds the main window of
//ESET Smart Security, otherwise, it finds the confirmation
//dialog box.
BOOL CALLBACK EnumWindowsProc(HWND hwnd, LPARAM lParam)
{
//Check if hwnd belongs to a window of egui.exe.
DWORD PID = 0;
GetWindowThreadProcessId(hwnd, &PID);
if (PID != EGUIPID)
return TRUE; //Exit function and continue the enumeration.

//Check if the title of the window is "ESET Smart Security"// or "ESET Node32 Antivirus".
int len = GetWindowTextLength(hwnd);
PSTR title = (PSTR) VirtualAlloc((LPVOID) NULL, (DWORD) (len + 1), MEM_COMMIT, PAGE_READWRITE);
GetWindowText(hwnd, title, (len + 1));
if ((lstrcmp(title, TEXT("ESET Smart Security"))) && (lstrcmp(title, TEXT("ESET NOD32 Antivirus"))))
return TRUE; //Exit function and continue the enumeration.

if (lParam)
{
//If lParam is nonzero and hwnd refers to the main
// window of egui.exe, exit function and continue
// the enumeration.
if (hwnd == ESETWindow)
return TRUE;
//Otherwise hwnd refers to the confirmation dialog box.
//So store it in the ConfirmationWindow variable.
ConfirmationWindow = hwnd;
return FALSE; //Exit function and stop the enumeration.
}
else
{
//hwnd refers to the main window of ESET Smart Security.
//So store it in the ESETWindow variable.
ESETWindow = hwnd;
return FALSE; //Exit function and stop the enumeration.
}
}
VOID SendAsyncProc(HWND hwnd, UINT uMsg, ULONG_PTR dwData, LRESULT lResult)
{
MessageBox(0, TEXT("ESET Smart Security was successfully terminated."), TEXT("Result"), MB_OK);
}

Хотя эта программа прекрасно справляется со своей задачей, функция обратного вызова SendAsyncProc не запускается после обработки сообщения WM_CLOSE и прекращения работы egui.exe. Не могли бы вы сказать мне, почему?