problem in run external program with QProcess

[JonB]

@saeid0034
Show your code now. Don't mix waitFor...()s with signals.

[saeid0034]

@JonB thanks, so this time i remove waitFor...() from my code and only use signal and slot, this time Finished Signal emited, with 0 QProcess::NormalExit, but i get unknow error too

[JonB]

@saeid0034
Better :) Don't use waitFor...()s again :) "unknown error" can also maybe if no error. Put in slots on readyReadStandardOutput()/Error() now?

[saeid0034]

@JonB both give me empty output

BigPAKC->readAllStandardOutput();
BigPAKC->readAllStandardError();

[JonB]

@saeid0034
I already suggested you try cmd /c dir but you would not. So far as I can see everything is working fine, you have not shown there is any actual problem.

You don't show code, so I can only hope your code is correctly in slots set up in the right places.

[saeid0034]

@JonB thanks, yes code seems working
i send my code above, it all code i use for qprocess.
and about cmd /c dir, what i'm supposed to do with it?

[JonB]

@saeid0034 said in problem in run external program with QProcess:

thanks, yes code seems working

If you mean everything is working then there is no issue,

i send my code above, it all code i use for qprocess.

You have shown fragments of code, which you say you have added to and deleted from. I do not know what your code looks like now.

and about cmd /c dir, what i'm supposed to do with it?

You were supposed to replace your process start()ing code by:
BigPAKC->start("cmd", QStringList() << "/c" << "dir");

EDIT
OMG, I have only just noticed in your code:

			if (!BigPAKC->waitForStarted())
				qDebug() << "started";
	         
			if (!BigPAKC->waitForFinished(-1))
				qDebug() << "Finished";

I did not see the !s. So you print nothing when all is well.... So what is your problem if it all worked fine from the outset?

[saeid0034]

@JonB Im worried about Unknown error but as you say its possible its mean no error

[JonB]

@saeid0034

QProcess::UnknownError 5 An unknown error occurred. This is the default return value of error().

No error occurred in your code. This has been a long discussion for that situation.

Why in the world did you write

			if (!BigPAKC->waitForStarted())
				qDebug() << "started";

instead of if (BigPAKC->waitForStarted()) ?

[saeid0034]

@JonB because i see example on https://doc.qt.io/qt-5/qprocess.html

[JonB]

@saeid0034
Your code:

			if (!BigPAKC->waitForStarted())
				qDebug() << "started";
	         
			if (!BigPAKC->waitForFinished(-1))
				qDebug() << "Finished";

Your description of what was wrong:

but my problem is both waitForStarted and waitForFinished never work, i mean waitForFinished doesnt wait for process to end and print Finished at start,

Why do you expect a successful waitForFinished() to print Finished here? Do you understand that with your use of ! it won't say anything when everything succeeds as it should?

[saeid0034]

@JonB sorry about that, i only see unknow error -_-
thanks about help