Why do I close the CMD window when debugging the program, and the destructor of the class object I create does not execute

Question

Answer 1

The destructor does not run because when the close button of a console window is clicked the system terminates the console process. This is not a normal termination.

You can see this by running the following sample code. It adds an atexit function that only runs on normal termination. It also adds a handler for console application events. When debugging observe the messages directed to the Output pane. You can see the difference between a normal termination and how the system otherwise terminates the process.

#define WIN32_LEAN_AND_MEAN
#include <Windows.h>

#include <conio.h>
#include <stdlib.h>
#include <stdio.h>
#include <tchar.h>

class Log
{
public:
    Log()
    {
        OutputDebugStringA("In Log Constructor\n");
    }

    ~Log()
    {
        OutputDebugStringA("In Log Destructor\n");
    }
};

void NormalTermination(void)
{
    OutputDebugStringA("Normal Termination\n");
}

BOOL CALLBACK Handler(DWORD CtrlType)
{
    switch (CtrlType)
    {
    case CTRL_C_EVENT:
        OutputDebugStringA("Ctrl-C\n");
        return FALSE;

    case CTRL_BREAK_EVENT:
        OutputDebugStringA("Ctrl-Break\n");
        return FALSE;

    case CTRL_CLOSE_EVENT:
        OutputDebugStringA("Ctrl-Close\n");
        return FALSE;

    case CTRL_LOGOFF_EVENT:
        OutputDebugStringA("Ctrl_Logoff\n");
        return FALSE;

    case CTRL_SHUTDOWN_EVENT:
        OutputDebugStringA("Ctrl-Shutdown\n");
        return FALSE;

    default:
        OutputDebugStringA("We shouldn't be here\n");
        return FALSE;
    }
}



int main()
{
    Log l;
    SetConsoleCtrlHandler(Handler, TRUE);
    atexit(NormalTermination);
    printf("Close Console Window now or hit enter to exit\n");
    _getch();

    return 0;
}