Clean File

[Bruno10x]

Hi everyone, I have a question, do I have a file like I do when I click a button to clean it all?

QFile file("txt.txt");
            if(!file.open(QIODevice::WriteOnly | QIODevice::Text))
                   return;
            file.close();

[mrjj]

Hi and welcome to the forums.
Im not 100% sure i understand what you ask.
You want to erase a file when you click the button or do you ask
if it will create an empty file, from the code shown?

[Bruno10x]

@mrjj Yes , I want erase a file when I click in a button.

[mrjj]

@Bruno10x
Hi
If you mean erase like in delete it, there is
http://doc.qt.io/qt-5/qfile.html#remove-1

Notice this is a static function
so you just call it like

QFile::remove( fullpathtofile.txt);

you dont need a QFile variable.

[Bruno10x]

@mrjj Ok, if I just want erase the content in file, How I do?

[Christian Ehrlicher]

@Bruno10x said in Clean File:

Ok, if I just want erase the content in file, How I do?

Open the file, read the fileSize and then do a QFile::write(QByteArray(0, filesize))

[JonB]

@Christian-Ehrlicher

You may have taken @Bruno10x's

Ok, if I just want erase the content in file,

a bit too literally :)

For his benefit: if by "erase content" you mean keep it same size but fill it with all bytes of value 0 then @Christian-Ehrlicher's solution is what you need. [Clarification: provided you know your file is not too large... (else do it in a loop with a buffer's-worth at a time)]

If you mean reset it to have length of zero, then your existing file.open(QIODevice::WriteOnly) should already be accomplishing that? [Clarification: http://doc.qt.io/qt-5/qiodevice.html#OpenModeFlag-enum

QIODevice::WriteOnly 0x0002 The device is open for writing. Note that this mode implies Truncate.

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