static int qt_native_select(fd_set *fdread, fd_set *fdwrite, int timeout){    struct timeval tv;    tv.tv_sec = timeout / 1000;    tv.tv_usec = (timeout % 1000) * 1000;    int ret;    do {        ret = select(FD_SETSIZE, fdread, fdwrite, 0, timeout < 0 ? 0 : &tv);    } while (ret < 0 && (errno == EINTR));    return ret;}/*   Returns the difference between msecs and elapsed. If msecs is -1,   however, -1 is returned.*/static int qt_timeout_value(int msecs, int elapsed){    if (msecs == -1)        return -1;    int timeout = msecs - elapsed;    return timeout < 0 ? 0 : timeout;}bool QProcessPrivate::waitForStarted(int msecs){    Q_Q(QProcess);#if defined (QPROCESS_DEBUG)    qDebug("QProcessPrivate::waitForStarted(%d) waiting for child to start (fd = %d)", msecs,	   childStartedPipe[0]);#endif    fd_set fds;    FD_ZERO(&fds);    FD_SET(childStartedPipe[0], &fds);    int ret;    do {        ret = qt_native_select(&fds, 0, msecs);    } while (ret < 0 && errno == EINTR);    if (ret == 0) {        processError = QProcess::Timedout;        q->setErrorString(QLatin1String(QT_TRANSLATE_NOOP(QProcess, "Process operation timed out")));#if defined (QPROCESS_DEBUG)        qDebug("QProcessPrivate::waitForStarted(%d) == false (timed out)", msecs);#endif        return false;    }    bool startedEmitted = _q_startupNotification();#if defined (QPROCESS_DEBUG)    qDebug("QProcessPrivate::waitForStarted() == %s", startedEmitted ? "true" : "false");#endif    return startedEmitted;}bool QProcessPrivate::waitForReadyRead(int msecs){    Q_Q(QProcess);#if defined (QPROCESS_DEBUG)    qDebug("QProcessPrivate::waitForReadyRead(%d)", msecs);#endif    QTime stopWatch;    stopWatch.start();    forever {        fd_set fdread;        fd_set fdwrite;        FD_ZERO(&fdread);        FD_ZERO(&fdwrite);        if (processState == QProcess::Starting)            FD_SET(childStartedPipe[0], &fdread);        if (stdoutChannel.pipe[0] != -1)            FD_SET(stdoutChannel.pipe[0], &fdread);        if (stderrChannel.pipe[0] != -1)            FD_SET(stderrChannel.pipe[0], &fdread);        FD_SET(deathPipe[0], &fdread);        if (!writeBuffer.isEmpty() && stdinChannel.pipe[1] != -1)            FD_SET(stdinChannel.pipe[1], &fdwrite);        int timeout = qt_timeout_value(msecs, stopWatch.elapsed());        int ret = qt_native_select(&fdread, &fdwrite, timeout);        if (ret < 0) {            if (errno == EINTR)                continue;            break;        }        if (ret == 0) {            processError = QProcess::Timedout;            q->setErrorString(QLatin1String(QT_TRANSLATE_NOOP(QProcess, "Process operation timed out")));	    return false;	}	if (childStartedPipe[0] != -1 && FD_ISSET(childStartedPipe[0], &fdread)) {            if (!_q_startupNotification())                return false;	}        bool readyReadEmitted = false;	if (stdoutChannel.pipe[0] != -1 && FD_ISSET(stdoutChannel.pipe[0], &fdread)) {	    bool canRead = _q_canReadStandardOutput();            if (processChannel == QProcess::StandardOutput && canRead)                readyReadEmitted = true;	}	if (stderrChannel.pipe[0] != -1 && FD_ISSET(stderrChannel.pipe[0], &fdread)) {	    bool canRead = _q_canReadStandardError();            if (processChannel == QProcess::StandardError && canRead)                readyReadEmitted = true;	}        if (readyReadEmitted)            return true;	if (stdinChannel.pipe[1] != -1 && FD_ISSET(stdinChannel.pipe[1], &fdwrite))	    _q_canWrite();	if (FD_ISSET(deathPipe[0], &fdread)) {            if (_q_processDied())                return false;        }    }    return false;}bool QProcessPrivate::waitForBytesWritten(int msecs){    Q_Q(QProcess);#if defined (QPROCESS_DEBUG)    qDebug("QProcessPrivate::waitForBytesWritten(%d)", msecs);#endif    QTime stopWatch;    stopWatch.start();    while (!writeBuffer.isEmpty()) {        fd_set fdread;        fd_set fdwrite;        FD_ZERO(&fdread);        FD_ZERO(&fdwrite);        if (processState == QProcess::Starting)            FD_SET(childStartedPipe[0], &fdread);        if (stdoutChannel.pipe[0] != -1)            FD_SET(stdoutChannel.pipe[0], &fdread);        if (stderrChannel.pipe[0] != -1)            FD_SET(stderrChannel.pipe[0], &fdread);        FD_SET(deathPipe[0], &fdread);        if (!writeBuffer.isEmpty() && stdinChannel.pipe[1] != -1)            FD_SET(stdinChannel.pipe[1], &fdwrite);	int timeout = qt_timeout_value(msecs, stopWatch.elapsed());	int ret = qt_native_select(&fdread, &fdwrite, timeout);        if (ret < 0) {            if (errno == EINTR)                continue;            break;        }        if (ret == 0) {	    processError = QProcess::Timedout;	    q->setErrorString(QLatin1String(QT_TRANSLATE_NOOP(QProcess, "Process operation timed out")));	    return false;	}	if (childStartedPipe[0] != -1 && FD_ISSET(childStartedPipe[0], &fdread)) {	    if (!_q_startupNotification())		return false;	}	if (stdinChannel.pipe[1] != -1 && FD_ISSET(stdinChannel.pipe[1], &fdwrite))	    return _q_canWrite();	if (stdoutChannel.pipe[0] != -1 && FD_ISSET(stdoutChannel.pipe[0], &fdread))	    _q_canReadStandardOutput();	if (stderrChannel.pipe[0] != -1 && FD_ISSET(stderrChannel.pipe[0], &fdread))	    _q_canReadStandardError();	if (FD_ISSET(deathPipe[0], &fdread)) {            if (_q_processDied())                return false;        }    }    return false;}bool QProcessPrivate::waitForFinished(int msecs){    Q_Q(QProcess);#if defined (QPROCESS_DEBUG)    qDebug("QProcessPrivate::waitForFinished(%d)", msecs);#endif    QTime stopWatch;    stopWatch.start();    forever {        fd_set fdread;        fd_set fdwrite;        FD_ZERO(&fdread);        FD_ZERO(&fdwrite);        if (processState == QProcess::Starting)            FD_SET(childStartedPipe[0], &fdread);        if (stdoutChannel.pipe[0] != -1)            FD_SET(stdoutChannel.pipe[0], &fdread);        if (stderrChannel.pipe[0] != -1)            FD_SET(stderrChannel.pipe[0], &fdread);        if (processState == QProcess::Running)            FD_SET(deathPipe[0], &fdread);        if (!writeBuffer.isEmpty() && stdinChannel.pipe[1] != -1)            FD_SET(stdinChannel.pipe[1], &fdwrite);	int timeout = qt_timeout_value(msecs, stopWatch.elapsed());	int ret = qt_native_select(&fdread, &fdwrite, timeout);        if (ret < 0) {            if (errno == EINTR)                continue;            break;        }	if (ret == 0) {	    processError = QProcess::Timedout;	    q->setErrorString(QLatin1String(QT_TRANSLATE_NOOP(QProcess, "Process operation timed out")));	    return false;	}	if (childStartedPipe[0] != -1 && FD_ISSET(childStartedPipe[0], &fdread)) {	    if (!_q_startupNotification())		return false;	}	if (stdinChannel.pipe[1] != -1 && FD_ISSET(stdinChannel.pipe[1], &fdwrite))	    _q_canWrite();	if (stdoutChannel.pipe[0] != -1 && FD_ISSET(stdoutChannel.pipe[0], &fdread))	    _q_canReadStandardOutput();	if (stderrChannel.pipe[0] != -1 && FD_ISSET(stderrChannel.pipe[0], &fdread))	    _q_canReadStandardError();	if (FD_ISSET(deathPipe[0], &fdread)) {            if (_q_processDied())                return true;	}    }    return false;}bool QProcessPrivate::waitForWrite(int msecs){    fd_set fdwrite;    FD_ZERO(&fdwrite);    FD_SET(stdinChannel.pipe[1], &fdwrite);    int ret;    do {        ret = qt_native_select(0, &fdwrite, msecs < 0 ? 0 : msecs) == 1;    } while (ret < 0 && errno == EINTR);    return ret == 1;}void QProcessPrivate::findExitCode(){    Q_Q(QProcess);    processManager()->remove(q);}bool QProcessPrivate::waitForDeadChild(){    Q_Q(QProcess);    // read a byte from the death pipe    char c;    qt_native_read(deathPipe[0], &c, 1);    // check if our process is dead    int exitStatus;    pid_t waitResult = waitpid(pid_t(pid), &exitStatus, WNOHANG);    if (waitResult > 0) {        processManager()->remove(q);        crashed = !WIFEXITED(exitStatus);        exitCode = WEXITSTATUS(exitStatus);#if defined QPROCESS_DEBUG        qDebug() << "QProcessPrivate::waitForDeadChild() dead with exitCode"                 << exitCode << ", crashed?" << crashed;#endif        return true;    }#if defined QPROCESS_DEBUG    qDebug() << "QProcessPrivate::waitForDeadChild() not dead!";#endif    return false;}void QProcessPrivate::_q_notified(){}/*! \internal */bool QProcessPrivate::startDetached(const QString &program, const QStringList &arguments){    processManager()->start();    // To catch the startup of the child    int startedPipe[2];    ::pipe(startedPipe);    pid_t childPid = fork();    if (childPid == 0) {        ::setsid();        ::signal(SIGHUP, SIG_IGN);        qt_native_close(startedPipe[0]);        ::signal(SIGPIPE, SIG_DFL);        pid_t doubleForkPid = fork();        if (doubleForkPid == 0) {            ::fcntl(startedPipe[1], F_SETFD, FD_CLOEXEC);            char **argv = new char *[arguments.size() + 2];            for (int i = 0; i < arguments.size(); ++i) {#ifdef Q_OS_MAC                argv[i + 1] = ::strdup(arguments.at(i).toUtf8().constData());#else                argv[i + 1] = ::strdup(arguments.at(i).toLocal8Bit().constData());#endif            }            argv[arguments.size() + 1] = 0;            if (!program.contains(QLatin1Char('/'))) {                const QString path = QString::fromLocal8Bit(::getenv("PATH"));                if (!path.isEmpty()) {                    QStringList pathEntries = path.split(QLatin1Char(':'));                    for (int k = 0; k < pathEntries.size(); ++k) {                        QByteArray tmp = QFile::encodeName(pathEntries.at(k));                        if (!tmp.endsWith('/')) tmp += '/';                        tmp += QFile::encodeName(program);                        argv[0] = tmp.data();                        qt_native_execv(argv[0], argv);                    }                }            } else {                QByteArray tmp = QFile::encodeName(program);                argv[0] = tmp.data();                qt_native_execv(argv[0], argv);            }            struct sigaction noaction;            memset(&noaction, 0, sizeof(noaction));            noaction.sa_handler = SIG_IGN;            qt_native_sigaction(SIGPIPE, &noaction, 0);            // '\1' means execv failed            char c = '\1';            qt_native_write(startedPipe[1], &c, 1);            qt_native_close(startedPipe[1]);            ::_exit(1);        } else if (doubleForkPid == -1) {            struct sigaction noaction;            memset(&noaction, 0, sizeof(noaction));            noaction.sa_handler = SIG_IGN;            qt_native_sigaction(SIGPIPE, &noaction, 0);            // '\2' means internal error            char c = '\2';            qt_native_write(startedPipe[1], &c, 1);        }        qt_native_close(startedPipe[1]);        qt_native_chdir("/");        ::_exit(1);    }    qt_native_close(startedPipe[1]);    if (childPid == -1) {        qt_native_close(startedPipe[0]);        return false;    }    char reply = '\0';    int startResult = qt_native_read(startedPipe[0], &reply, 1);    int result;    qt_native_close(startedPipe[0]);    ::waitpid(childPid, &result, 0);    return startResult != -1 && reply == '\0';}void QProcessPrivate::initializeProcessManager(){    (void) processManager();}#include "qprocess_unix.moc"#endif // QT_NO_PROCESS