New to Qt, could use some help with Qprocess
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I am trying to read and write from a qprocess right now. I made a little test program that takes input and redisplays it on the screen in a loop. Here is my code from Qt
@QString path = "./test";
tcd = new QProcess(this); QStringList args; args << ""; tcd->start(path,args); if(!tcd->waitForStarted(3000)) { stdoutput->append("<h1><font color=red>There was a problem starting the software, please try running the program again.</font></h1>"); } tcd->write("hellon"); tcd->write("hellon"); tcd->write("hellon"); tcd->write("hellon"); //tcd->write("quitn");QObject::connect(tcd, SIGNAL(readyReadStandardOutput()), this, SLOT(appendTextBox()));
This won't work unless I send that last quit command (which terminates my test program).
@
Here's my read command:@void TCD2_GUI::appendTextBox(){
stdoutput->append("new output available: n");
QByteArray newData = tcd->readAllStandardOutput();
stdoutput->append(QString::fromLocal8Bit(newData));
}@
if I send quit, I will get all the output from the program at once, including everything I have sent it.What am I doing wrong here?
here is the code from the program:
@int main(int argC[], char* argV[]){
printf("Welcome!n");
char* input = malloc(160);
gets(input);while(strcmp(input,"quit") != 0) { printf("Got input %sn", input); gets(input); }}@
I also noticed that if I call close on the Qprocess, I wont read anything, it's only when I send the program the "quit" message
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Normally, stdout is buffered. So you should
@
fflush(stdout);
@in your test program after printf'ing the input.
You might also have a look at Qt's "QTextStream":http://doc.qt.nokia.com/4.7/qtextstream.html and "QDataStream":http://doc.qt.nokia.com/4.7/qdatastream.html classes for the io.