C++ QSharedMemory::constData方法代码示例

/**
 * @brief Executed when new instance connect command is sent to LocalServer
 */
void Rshare::slotConnectionEstablished()
{
	QLocalSocket *socket = localServer->nextPendingConnection();
	socket->close();
	delete socket;

	QSharedMemory newArgs;
	newArgs.setKey(QString(TARGET) + "_newArgs");

	if (!newArgs.attach())
	{
		std::cerr << "(EE) Rshare::slotConnectionEstablished() Unable to attach to shared memory segment."
		          << newArgs.errorString().toStdString() << std::endl;
		return;
	}

	QBuffer buffer;
	QDataStream in(&buffer);
	QStringList args;

	newArgs.lock();
	buffer.setData((char*)newArgs.constData(), newArgs.size());
	buffer.open(QBuffer::ReadOnly);
	in >> args;
	newArgs.unlock();
	newArgs.detach();

	emit newArgsReceived(args);
	while (!args.empty())
	{
		std::cerr << "Rshare::slotConnectionEstablished args:" << QString(args.takeFirst()).toStdString() << std::endl;
	}
}

void conflict_core::updateAida(){
    QBuffer buffer;
    QDataStream in(&buffer);
    QString text;
    if(conflict.aidaOpen){
        aida.lock();
        buffer.setData((char*)aida.constData(), aida.size());
        buffer.open(QBuffer::ReadOnly);
        in >> text;
        ui->debugOutputOut->append(text);
        aida.unlock();
    }

// Example how to get json using shared memory. Not tested :-D
std::pair<bool, QString> json() {

    QSharedMemory sharedMemory;

    if (!sharedMemory.attach()) {
        return std::make_pair<bool, QString>(false, QString());
    }

    QBuffer buffer;
    QDataStream in(&buffer);
    QString json;

    sharedMemory.lock();
    buffer.setData((char*)sharedMemory.constData(), sharedMemory.size());
    buffer.open(QBuffer::ReadOnly);
    in >> json;
    sharedMemory.unlock();

    sharedMemory.detach();
    return std::make_pair<bool, QString>(false, QString());
}

// Check if the application is running. Optionally write something to its shared memory.
static bool isRunning(const char* command){
    // Try to create shared memory (if successful, application was not already running)
    if(!appShare.create(SHMEM_SIZE) || !appShare.lock()){
        // Lock existing shared memory
        if(!appShare.attach() || !appShare.lock())
            return true;
        bool running = false;
        if(appShare.size() == SHMEM_SIZE_V015){
            // Old shmem - no PID listed so assume the process is running, and print the command directly to the buffer
            if(command){
                void* data = appShare.data();
                snprintf((char*)data, SHMEM_SIZE_V015, "%s", command);
            }
            running = true;
        } else {
            // New shmem. Scan the contents of the shared memory for a PID
            QStringList lines = QString((const char*)appShare.constData()).split("\n");
            if(pidActive(lines)){
                running = true;
                // Append the command
                if(command){
                    lines.append(QString("Option ") + command);
                    QByteArray newMem = lines.join("\n").left(SHMEM_SIZE).toLatin1();
                    // Copy the NUL byte as well as the string
                    memcpy(appShare.data(), newMem.constData(), newMem.length() + 1);
                }
            }
        }
        if(running){
            appShare.unlock();
            return true;
        }
    }
    // Not already running. Initialize the shared memory with our PID
    snprintf((char*)appShare.data(), appShare.size(), "PID %ld", (long)getpid());
    appShare.unlock();
    return false;
}

char* address_jt9_() {return (char*)mem_jt9.constData();}