After testing under windows, it is found that QT program will kill the process created by CreateProcess when it exits again

[legahero]

MinGW32，After testing under windows, it is found that QT program will kill the process created by CreateProcess when it exits again，I tested the following situations, but there were no exceptions（windows下经过测试发现QT编写的程序再退出的时候会把CreateProcess创建的进程杀死，我测试了以下各种情况但都没有例外），following code:
#include "bccmainwindow.h"
#include "ui_bccmainwindow.h"
#include <QProcess>
#include <QDebug>
#include <QDir>
//#include <windows.h>
#include "qsystemlibrary.h"

static QString qt_create_commandline(const QString &program, const QStringList &arguments);
static bool startDetachedUacPrompt(const QString &programIn, const QStringList &arguments,
const QString &workingDir, qint64 *pid);
bool startDetached(const QString &program, const QStringList &arguments, const QString &workingDir, qint64 *pid);

using namespace std;
BccMainWindow::BccMainWindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::BccMainWindow)
{
ui->setupUi(this);
}

BccMainWindow::~BccMainWindow()
{
delete ui;
}

void BccMainWindow::on_pushButton_clicked()
{

QProcess* process  = new QProcess;
//QString strpath = qApp->applicationDirPath();
//process->setWorkingDirectory(strpath + QString("/softwares/com2tcp"));
//QString str_exePath = "\"" + str_exePath + "\"";
QStringList arguments;

arguments << "-new" << "http://www.qq.com";



if (process->state() != QProcess::Running)
{   /// 只允许开启一个进程
     process->startDetached("C:\\Program Files (x86)\\Internet Explorer\\iexplore.exe ", arguments);     // 将以阻塞的方式启动
     //process->start("C:\\Program Files (x86)\\Internet Explorer\\iexplore.exe ", arguments);
     if(!process->waitForStarted())
     {
         qDebug() << "waitForStarted false";
     }
     //process->waitForFinished(5000);
     QString strResult = QString::fromLocal8Bit(process->readAllStandardOutput());
     qDebug() << strResult;
}


if(process)
{
    //process->close();
    delete process;
    process = NULL;
}

}

void BccMainWindow::on_pushButton_2_clicked()
{
QDir::setCurrent("C:\Program Files (x86)\Internet Explorer\");

QStringList arguments;
arguments << "-new" << "http://www.qq.com";
if(!QProcess::startDetached("iexplore.exe",arguments))
{
    qDebug() << "startDetached false";
}

}

void BccMainWindow::on_pushButton_3_clicked()
{
/*
QDir::setCurrent("C:\Program Files (x86)\Internet Explorer\");
int code=QProcess::execute("iexplore.exe -new www.qq.com");

qDebug() << "execute code "<<code;
*/
/*

#define SW_NORMAL 1 //普通方式运行
#define SW_SHOWMINIMIZED 2 //运行时最小化显示
#define SW_SHOWMAXIMIZED 3 //运行时最大化显示
#define SW_MAXIMIZE 3 //最大化运行
*/
WinExec(""C:\Program Files (x86)\Internet Explorer\iexplore.exe" -new www.qq.com",1);

}

void BccMainWindow::on_pushButton_4_clicked()
{
QDir::setCurrent("C:\Program Files (x86)\Internet Explorer\");

QStringList arguments;
arguments << "-new" << "http://www.qq.com";

if(!QProcess::execute("iexplore.exe",arguments))
{
    qDebug() << "execute false";
}

}
/*
QProcess ps;

connect(&ps,SIGNAL(readyReadStandardOutput()),this,SLOT(readProcessStandardOutput()));

QStringList args;

args<<"-c";

args<<"ps | grep 'processName";

ps.start("sh",args);

readProcessStandardOutput()

{
ps.readAllStandardOutput() // 得到sh -c "ps | grep 'processName‘“ 的输出结果，查看这个结果就可以得到这个结果是否在运行。

}
*/

void BccMainWindow::on_pushButton_cmd_clicked()
{
QDir::setCurrent("C:\Program Files (x86)\Internet Explorer\");

QStringList arguments;
arguments<<"/c"<<"iexplore.exe -new \"http://www.qq.com\"";

qint64 pid;
//if(!QProcess::startDetached("cmd",arguments,"C:\\Program Files (x86)\\Internet Explorer\\",&pid))
if(!startDetached("cmd",arguments,"C:\\Program Files (x86)\\Internet Explorer\\",&pid))
{
    qDebug() << "startDetached false";
}

/*
qint64 ProcessId;

HANDLE hProcess = OpenProcess(PROCESS_TERMINATE, FALSE, pid);
if (hProcess == NULL)
{
    //return FALSE;
}
if (!TerminateProcess(hProcess, 0))
{
    //return FALSE;
}
*/
//return TRUE;

}

static QString qt_create_commandline(const QString &program, const QStringList &arguments)
{
QString args;
if (!program.isEmpty()) {
QString programName = program;
if (!programName.startsWith(QLatin1Char('"')) && !programName.endsWith(QLatin1Char('"')) && programName.contains(QLatin1Char(' ')))
programName = QLatin1Char('"') + programName + QLatin1Char('"');
programName.replace(QLatin1Char('/'), QLatin1Char('\'));

    // add the prgram as the first arg ... it works better
    args = programName + QLatin1Char(' ');
}

for (int i=0; i<arguments.size(); ++i) {
    QString tmp = arguments.at(i);
    // Quotes are escaped and their preceding backslashes are doubled.
    tmp.replace(QRegExp(QLatin1String("(\\\\*)\"")), QLatin1String("\\1\\1\\\""));
    if (tmp.isEmpty() || tmp.contains(QLatin1Char(' ')) || tmp.contains(QLatin1Char('\t'))) {
        // The argument must not end with a \ since this would be interpreted
        // as escaping the quote -- rather put the \ behind the quote: e.g.
        // rather use "foo"\ than "foo\"
        int i = tmp.length();
        while (i > 0 && tmp.at(i - 1) == QLatin1Char('\\'))
            --i;
        tmp.insert(i, QLatin1Char('"'));
        tmp.prepend(QLatin1Char('"'));
    }
    args += QLatin1Char(' ') + tmp;
}
return args;

}

// Use ShellExecuteEx() to trigger an UAC prompt when CreateProcess()fails
// with ERROR_ELEVATION_REQUIRED.
static bool startDetachedUacPrompt(const QString &programIn, const QStringList &arguments,
const QString &workingDir, qint64 *pid)
{
typedef BOOL (WINAPI *ShellExecuteExType)(SHELLEXECUTEINFOW *);

static const ShellExecuteExType shellExecuteEx = // XP ServicePack 1 onwards.
    reinterpret_cast<ShellExecuteExType>(QSystemLibrary::resolve(QLatin1String("shell32"),
                                                                 "ShellExecuteExW"));
if (!shellExecuteEx)
    return false;

const QString args = qt_create_commandline(QString(), arguments); // needs arguments only
SHELLEXECUTEINFOW shellExecuteExInfo;
memset(&shellExecuteExInfo, 0, sizeof(SHELLEXECUTEINFOW));
shellExecuteExInfo.cbSize = sizeof(SHELLEXECUTEINFOW);
shellExecuteExInfo.fMask = SEE_MASK_NOCLOSEPROCESS | SEE_MASK_UNICODE | SEE_MASK_FLAG_NO_UI;
shellExecuteExInfo.lpVerb = L"runas";
const QString program = QDir::toNativeSeparators(programIn);
shellExecuteExInfo.lpFile = reinterpret_cast<LPCWSTR>(program.utf16());
if (!args.isEmpty())
    shellExecuteExInfo.lpParameters = reinterpret_cast<LPCWSTR>(args.utf16());
if (!workingDir.isEmpty())
    shellExecuteExInfo.lpDirectory = reinterpret_cast<LPCWSTR>(workingDir.utf16());
shellExecuteExInfo.nShow = SW_SHOWNORMAL;

if (!shellExecuteEx(&shellExecuteExInfo))
    return false;
if (pid)
    *pid = qint64(GetProcessId(shellExecuteExInfo.hProcess));
CloseHandle(shellExecuteExInfo.hProcess);
return true;

}

bool startDetached(const QString &program, const QStringList &arguments, const QString &workingDir, qint64 *pid)
{
static const DWORD errorElevationRequired = 740;

QString args = qt_create_commandline(program, arguments);
bool success = false;
PROCESS_INFORMATION pinfo;

DWORD dwCreationFlags = (GetConsoleWindow() ? 0 : CREATE_NO_WINDOW);
dwCreationFlags |= CREATE_UNICODE_ENVIRONMENT;
dwCreationFlags |= DETACHED_PROCESS;
STARTUPINFOW startupInfo = { sizeof( STARTUPINFO ), 0, 0, 0,
                             (ulong)CW_USEDEFAULT, (ulong)CW_USEDEFAULT,
                             (ulong)CW_USEDEFAULT, (ulong)CW_USEDEFAULT,
                             0, 0, 0, 0, 0, 0, 0, 0, 0, 0
                           };
success = CreateProcess(0, (wchar_t*)args.utf16(),
                        0, 0, FALSE, dwCreationFlags, 0,
                        workingDir.isEmpty() ? 0 : (wchar_t*)workingDir.utf16(),
                        &startupInfo, &pinfo);

if (success) {
    CloseHandle(pinfo.hThread);
    CloseHandle(pinfo.hProcess);
    if (pid)
        *pid = pinfo.dwProcessId;
} else if (GetLastError() == errorElevationRequired) {
    success = startDetachedUacPrompt(program, arguments, workingDir, pid);
}

return success;

}

void BccMainWindow::on_pushButton_CreateP_clicked()
{
char cWindowsDirectory[MAX_PATH] = { 0 };

    //LPTSTR 与 wchar_t* 等价(Unicode环境下)
    LPTSTR cWinDir = new TCHAR[MAX_PATH];
    memset(cWinDir, MAX_PATH, 0);
    //GetCurrentDirectory(MAX_PATH, cWinDir);

    
    wcscpy_s(cWinDir, MAX_PATH, L"D:\\Tool\\DevMng.exe");
    LPTSTR sConLin = cWinDir;

    STARTUPINFO si;
    PROCESS_INFORMATION pi;

    ZeroMemory(&si, sizeof(si));
    ZeroMemory(&pi, sizeof(pi));

    //创建一个新进程
    if (CreateProcess(
        NULL,   //  指向一个NULL结尾的、用来指定可执行模块的宽字节字符串
        sConLin, // 命令行字符串
        NULL, //    指向一个SECURITY_ATTRIBUTES结构体，这个结构体决定是否返回的句柄可以被子进程继承。
        NULL, //    如果lpProcessAttributes参数为空（NULL），那么句柄不能被继承。<同上>
        false,//    指示新进程是否从调用进程处继承了句柄。
        0,  //  指定附加的、用来控制优先类和进程的创建的标
            //  CREATE_NEW_CONSOLE  新控制台打开子进程
            //  CREATE_SUSPENDED    子进程创建后挂起，直到调用ResumeThread函数
        NULL, //    指向一个新进程的环境块。如果此参数为空，新进程使用调用进程的环境
        NULL, //    指定子进程的工作路径
        &si, // 决定新进程的主窗体如何显示的STARTUPINFO结构体
        &pi  // 接收新进程的识别信息的PROCESS_INFORMATION结构体
    ))
    {
        qDebug() << "create process success" << endl;

        //下面两行关闭句柄，解除本进程和新进程的关系，不然有可能不小心调用TerminateProcess函数关掉子进程
//      CloseHandle(pi.hProcess);
//      CloseHandle(pi.hThread);
    }
    else {
        qDebug() << "failed to create process" << endl;
    }
    ::GetCurrentProcess();
    Sleep(1000);

    //终止子进程
    //TerminateProcess(pi.hProcess, 300);

    //终止本进程，状态码
    //ExitProcess(1001);

    //return 0;

}

[legahero]

I hope that when the main process exits, it does not exit other processes it started，It's useful in some scenarios, such as program upgrades（我希望主进程退出时不会退出它启动的其它进程，在某些场景下还是有用的，比如程序升级），Now I have to use other development tools to finish it.

[JKSH]

@legahero said in After testing under windows, it is found that QT program will kill the process created by CreateProcess when it exits again:

I hope that when the main process exits, it does not exit other processes it started

Then your other child process must be detached.

Anyway, I see that your code contains both QProcess and CreateProcess. It doesn't make sense to mix both in the same application, so you should just choose one. (I think QProcess is a lot simpler to use)

If you have further questions, please clean up and simplify your code.

[legahero]

@JKSH ,thanks,I find that this happens when debugging, not when publishing。