QFile - File not writing on OS X

Tavis

Hello, I am trying to use QFile to write / read a simple text file and I am getting "Unknown error" and error number 0. The file does get created but no data is writing to it. I have the same problem trying to open and read a file. Same error.

The only way I can get it to write to the file is if I don't specify a path like so:

    QFile mFile("test.txt");

But when I do this, the file ends up sitting inside the applications package contents: myFileIO.app/Contents/MacOS/test.txt

So I'd like to figure out how to get this to read/write to a path outside of the location of the executable itself.

Here is my test code:

void Write ()
{
    QFile mFile("/Users/Shared/test.txt");

    if(!mFile.open(QFile::WriteOnly) | QFile::Text){
        qDebug() << "Could not open file for writing";
        qDebug() << "exists?              " << mFile.exists();
        qDebug() << "writable?            " << mFile.isWritable();
        qDebug() << "permissions?   " << mFile.permissions();
        qDebug() << "errors?              " << mFile.errorString();
        qDebug() << "errnum?              " << mFile.error();

    }
    mFile.close();
    QTextStream out(&mFile);
    out << "hello world";
    mFile.flush();
    mFile.close();
}

And this is the output i am getting:

Could not open file for writing
exists?               true
writable?             true
permissions?    QFlags(0x4|0x40|0x200|0x400|0x2000|0x4000)
errors?               "Unknown error"
errnum?               0
QIODevice::write (QFile, "/Users/Shared/test.txt"): device not open

Any ideas?

Thanks,

Tavis

MrKozmon

Because you closed your mFile before QTextStream write:

...
mFile.close(); // << Remove that
QTextStream out(&mFile);
...

Rondog

In addition to closing the file:

the path should be verified. A typical user path name is something like '/Users/<user-name>/'. Maybe a QFileDialog should be used to pick a file name to write would be better (or use the home path).
the test to open the file is wrong:

if(!mFile.open(QFile::WriteOnly) | QFile::Text){
\\ should be
if(!mFile.open(QFile::WriteOnly | QFile::Text)){

you should call 'flush' on the QTextStream and not on 'mFile'. I have seen issues where you might have the text file truncated if used the way it is. If you happen to have QTextStream go out of scope it works fine then.

Tavis

That did it.. Thanks.