QProcess::readyReadStandardError on Qt4

Sameer

Here's a snippet of my code. I am using a QProcess to launch a "bad" unix command. The "readyReadStandardError" signal is connected to a slot.

On Qt5.6, this slot gets fired. But on Qt4.8, the slot isn't getting fired.

Any ideas about what's going on?

MyClass::MyClass() {
m_process = new QProcess(this);
connect(m_process, SIGNAL(readyReadStandardOutput()), this, SLOT(onReadyReadStandardOutput()));
connect(m_process, SIGNAL(readyReadStandardError()), this, SLOT(onReadyReadStandardError()));

 QString cmd = "/bin/sh -c \"/bin/foo\"";
 m_process->start(cmd);
 m_process->waitForFinished();

}

void MyClass::onReadyReadStandardOutput() {
std::cout << "Output Ready!!!" << std::endl;
}

void MyClass::onReadyReadStandardError() {
std::cout << "Error Ready!!!" << std::endl;
}

SGaist

Hi and welcome to devnet,

You should check the error code you get from the execution of your command.

Sameer

Thanks!

After m_process->waitForFinished()

m_process->errorString() returns "Unknown error"
m_process->exitCode() returns 127 (which is the unix return code for invalid commands)

I am trying to read any errors in the slot and print them to a transcript window.
Things work fine on Qt5.
On Qt4, the error goes directly to the terminal that the Qt application is run from and the slot is never called.

SGaist

What version of Qt 4 ?