QFile write isn't stable

[ruben.rodrigues]

Hi all!

I have a client-server application and the network settings are loaded from a txt file that can be overwritten by the administrator but I am have some problems writing the textstream to the file.

the txt file looks like this:

192.168.1.220
11001

this is the function to write:

QFile file("/opt/esp/Client/Settings/CL_settings.txt");
if (!file.open(QIODevice::WriteOnly))
    return;
 
QTextStream out(&file);
out << ui.lineEdit_16->text() << "\n" << ui.lineEdit_17->text() << endl;

QFile file("/opt/esp/Client/Settings/CL_settings.txt");
if (!file.open(QIODevice::WriteOnly))
    return;

QTextStream out(&file);
out << ui.lineEdit_16->text() << "\n" << ui.lineEdit_17->text() << endl;

To copy to clipboard, switch view to plain text mode 

the open and reading part works perfectly but when I write with that function, sometime it writes the first line and then the second, other times writes a blank line in the middle, then 2 blank lines, and maybe then back to normal...

I tried other ways:

out << ui.lineEdit_16->text() << "\n" << ui.lineEdit_17->text();

out << ui.lineEdit_16->text() << "\n" << ui.lineEdit_17->text();

To copy to clipboard, switch view to plain text mode 

out << ui.lineEdit_16->text() << "\n"
out << ui.lineEdit_17->text();

out << ui.lineEdit_16->text() << "\n"
out << ui.lineEdit_17->text();

To copy to clipboard, switch view to plain text mode 

out << ui.lineEdit_16->text();
out << ui.lineEdit_17->text();

out << ui.lineEdit_16->text();
out << ui.lineEdit_17->text();

To copy to clipboard, switch view to plain text mode 

out << ui.lineEdit_16->text() + out << ui.lineEdit_17->text();

out << ui.lineEdit_16->text() + out << ui.lineEdit_17->text();

To copy to clipboard, switch view to plain text mode 

out << ui.lineEdit_16->text() << "\n"
     << ui.lineEdit_16->text();

out << ui.lineEdit_16->text() << "\n"
     << ui.lineEdit_16->text();

To copy to clipboard, switch view to plain text mode 

they all give me the same problem and my co-worker has a program that does the same thing and it works well for him.

thanks in advance

[JD2000]

Where is the text in your line edits coming from and how is it being set?

[wysota]

Maybe more than one instance of the application (or some other application) tries to write to the same file at the same time? Also you don't seem to be truncating the file so you overwrite old contents but if new contents is shorter than the old then the part that is not overwritten will still be in the file (so if your file was 20 bytes long and you open it for writing and write 10 bytes, it will still be 20 bytes long).