Problems communicating with a process (Gnuchess) via QProcess

[momesana]

Hi,
I can't get to communicate with Gnuchess. When I start it using the -x flag nothing happens, and there is no data at all to read from. If I start it without any commandline flags I get some info about gnuchess and I (white) am prompted to make my move but it won't react to any of the commands I write to it using QProcess::write():



GNU Chess 5.07
Adjusting HashSize to 1024 slots
Transposition table: Entries=1K Size=40K
Pawn hash table: Entries=0K Size=28K
White (1) :


Below is a minimal test app I've made to show the problem. You will most likely have to edit line 35 and change the path to gnuchess if you want it to work. Of course Gnuchess needs to be installed ;-). Any ideas?

Thanks in advance




#include <QtGui>
#include <QDebug>

class MainWindow : public QMainWindow
{
Q_OBJECT
public:
MainWindow(QWidget* parent = 0) : QMainWindow(parent) {
m_log = new QTextBrowser;

m_lineEdit = new QLineEdit;
connect(m_lineEdit, SIGNAL(returnPressed()), this, SLOT(send()));

QPushButton* sendButton = new QPushButton(tr("Send"));
connect(sendButton, SIGNAL(clicked()), this, SLOT(send()));

QPushButton* receiveButton = new QPushButton(tr("Read"));
connect(receiveButton, SIGNAL(clicked()), this, SLOT(readDataOnButtonPress()));

QHBoxLayout* blo = new QHBoxLayout;
blo->addWidget(m_lineEdit);
blo->addWidget(sendButton);
blo->addWidget(receiveButton);

QWidget* cw = new QWidget;
QVBoxLayout* hlo = new QVBoxLayout;
cw->setLayout(hlo);
hlo->addWidget(m_log);
hlo->addLayout(blo);

m_engine = new QProcess(this);
m_engine->setProcessChannelMode(QProcess::MergedChannels);
m_engine->setReadChannel(QProcess::StandardOutput);
connect(m_engine, SIGNAL(readyRead()), this, SLOT(readData()));
m_engine->start("/usr/games/bin/gnuchess", QStringList() << "-x");

setCentralWidget(cw);
}

~MainWindow() {
m_engine->terminate();
m_engine->kill();
}

private:
QTextBrowser* m_log;
QProcess* m_engine;
QLineEdit* m_lineEdit;

private slots:
void readData() {
QByteArray ba;

ba = m_engine->readAllStandardOutput().trimmed();
if (!ba.trimmed().isEmpty()) {
m_log->append(ba);
}

ba = m_engine->readAllStandardError().trimmed();
if (!ba.trimmed().isEmpty()) {
m_log->append(ba);
}
}

void readDataOnButtonPress()
{
QString info;

info.append("----------------\n");
info.append(QString("bytes available: %1\n").arg(m_engine->bytesAvailable()));
info.append("----------------\n");

m_log->append(info);

readData();
}

void send() {
QString text = m_lineEdit->text().trimmed();
m_lineEdit->clear();

if (text.isEmpty())
return;

m_engine->write(text.toAscii());
m_log->append(text);
}
};

int main(int argc, char** argv)
{
QApplication app(argc, argv);
MainWindow mw;
mw.setWindowTitle(QObject::tr("QProcess test"));
mw.show();
return app.exec();
}

#include "main.moc"

[danbetz]

try to send not only a command but also a newline.