Windows - STARTUPINFO의 cbReserved2, lpReserved2 멤버 사용자 정의

원래 STARTUPINFO의 문서를 보면,

STARTUPINFOA structure (processthreadsapi.h)
; https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/ns-processthreadsapi-startupinfoa

cbReserved2

Reserved for use by the C Run-time; must be zero.

lpReserved2

Reserved for use by the C Run-time; must be NULL.

Undocumented CreateProcess 
; https://is.muni.cz/el/1433/jaro2010/PB167/um/cv5/undocumented_CreateProcess.pdf

// ConsoleApplication2.exe

#include <iostream>
#include <Windows.h>

int main(int argc, char** argv)
{
    STARTUPINFOW si;
    GetStartupInfoW(&si);

    printf("ConsoleApplication2: %d, %p\n", si.cbReserved2, si.lpReserved2);
}

// 실행 결과 (대개의 경우, 명령행에서 실행하든, 탐색기에서 실행하든!)
// ConsoleApplication2: 0, 0000000000000000

// ConsoleApplication1.exe

#include <iostream>
#include <Windows.h>

int main()
{
    std::cout << "Hello ConsoleApplication1!\n";

    PROCESS_INFORMATION pi = { 0, };
    STARTUPINFOW si = { 0, };

    BYTE data[4] = { 0xff, 0xff, 0xff, 0xff };
    si.cbReserved2 = 4;
    si.lpReserved2 = data;

    wchar_t buffer[1024] = L"ConsoleApplication2.exe";

    si.cb = sizeof(STARTUPINFOW);
    if (!CreateProcessW(NULL, buffer, NULL, NULL, FALSE, 0, NULL, NULL, &si, &pi))
    {
        printf("CreateProcess failed (%d).\n", GetLastError());
        return 0;
    }

    WaitForSingleObject(pi.hProcess, INFINITE);

    CloseHandle(pi.hProcess);
    CloseHandle(pi.hThread);
}

Faulting application name: ConsoleApplication2.exe, version: 0.0.0.0, time stamp: 0x66cfb8eb
Faulting module name: ucrtbase.dll, version: 10.0.22621.3593, time stamp: 0x10c46e71
Exception code: 0xc0000409
Fault offset: 0x000000000007e008
Faulting process id: 0x0x9ECC
Faulting application start time: 0x0x1DAF9A7EA409387
Faulting application path: c:\temp\ConsoleApplication1\x64\Debug\ConsoleApplication2.exe
Faulting module path: C:\WINDOWS\System32\ucrtbase.dll
Report Id: de6a3081-16d3-44fd-8e55-1473bcdcdf03
Faulting package full name: 
Faulting package-relative application ID: 

C/C++ - CRT(C Runtime) 함수에 의존성이 없는 프로젝트 생성
; https://www.sysnet.pe.kr/2/0/13722

************* Path validation summary **************
...[생략]...
Executable search path is: 
ModLoad: 00007ff6`dea30000 00007ff6`deb32000   conhost.exe
ModLoad: 00007ffe`6d890000 00007ffe`6daa7000   ntdll.dll
ModLoad: 00007ffe`6c500000 00007ffe`6c5c4000   C:\WINDOWS\System32\KERNEL32.DLL
ModLoad: 00007ffe`6ad30000 00007ffe`6b0dd000   C:\WINDOWS\System32\KERNELBASE.dll
ModLoad: 00007ffe`6b3b0000 00007ffe`6b44a000   C:\WINDOWS\System32\msvcp_win.dll
ModLoad: 00007ffe`6b290000 00007ffe`6b3a1000   C:\WINDOWS\System32\ucrtbase.dll
(dc54.9468): Break instruction exception - code 80000003 (first chance)
ntdll!LdrpDoDebuggerBreak+0x30:
00007ffe`6d96c084 cc              int     3

DWORD  count; 
BYTE   flags[count]; 
HANDLE handles[count]; 

// in memory these are layed out sequentially: 
[ count ][ flags... ][ handles... ] 

BYTE data[] = { 0, 0, 0, 0, 'H', 'e', 'l', 'l', 'o', '\0'};
si.cbReserved2 = 10;
si.lpReserved2 = data;

#include <Windows.h>

int mainCRTStartup()
{
    STARTUPINFOW si;
    GetStartupInfoW(&si);

    char buffer[1024];
    int length = wsprintfA(buffer, "%d, %s\n", si.cbReserved2, si.lpReserved2 + 4);
    
    {
        HANDLE hOutput = ::GetStdHandle(STD_OUTPUT_HANDLE);
        if (hOutput != INVALID_HANDLE_VALUE)
        {
            DWORD dwWritten = 0;
            ::WriteConsoleA(hOutput, buffer, length, &dwWritten, nullptr);
        }
    }

    return 0;
}