Qt - Wait for Qprocess to finish

Question

I'm using CMD by QProcess but I have a problem.

My code:

QProcess process;
process.start("cmd.exe");
process.write ("del f:\\b.txt\n\r");
process.waitForFinished();
process.close();

When I don't pass an argument for waitForFinished() it waits for 30 secs. I want to terminate QProcess after CMD command is executed! Not much and not less!

ahmed · Accepted Answer · 2014-08-01T16:16:17.237

10

You need to terminate the cmd.exe by sending exit command, otherwise it will wait for commands Here is my suggestion:

QProcess process;
process.start("cmd.exe");
process.write ("del f:\\b.txt\n\r");
process.write ("exit\n\r");
process.waitForFinished();
process.close();

edited Aug 01 '14 at 16:16

answered Jul 31 '14 at 16:08

ahmed

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TheDarkKnight · Answer 2 · 2014-07-31T14:55:50.350

6

The process you're starting is cmd.exe which, by itself will, not terminate. If you call cmd with arguments, you should achieve what you want: -

QProcess process;
process.start("cmd.exe \"del f:\\b.txt"\"");
process.waitForFinished();
process.close();

Note that the arguments are escaped in quotes.

Alternatively, you could call the del process, without cmd: -

QProcess process;
process.start("del \"f:\\b.txt"\"");
process.waitForFinished();
process.close();

Finally, if you just want to delete a file, you could use the QFile::remove function.

QFile file("f:\\b.txt");
if(file.remove())
    qDebug() << "File removed successfully";

edited Jul 31 '14 at 14:55

answered Jul 31 '14 at 14:49

TheDarkKnight

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Just for the sake of completion, as your anwser demonstrates several ways, I would add that passing -1 to QProcess::waitForFinished, would not trigger any timeout – epsilon Jul 31 '14 at 14:56
It waits long And also did not work! It`s a sample code. I want to use CMD for other jobs not deleting – Mohammad Reza Ramezani Jul 31 '14 at 14:58
If you're using command for other tasks, it would be easier (in my opinion) to create a script and call that from QProcess. – TheDarkKnight Jul 31 '14 at 14:59
2

@MohammadRezaRamezani Same advice as Merlin069. Create a batch, run it as its answer show. – epsilon Jul 31 '14 at 15:02
@jbh All thing I need it in the first post. I wnat use mentioned code and wait to finish command prpmt completion not 30secs – Mohammad Reza Ramezani Jul 31 '14 at 15:04

Qt - Wait for Qprocess to finish

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