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SetFileTime on an image, File::open set filesize to 0



  • Hello, i have a problem using QFile::setFileTime, when i try to open a ".jpg" file, the file's size is automatically set to 0. However, i have to open the file to setFileTime...

    bool copyFileKeepingMetadatas(const QString& origin, const QString& destination) {
        QFileInfo fileInfo(origin);
        QDateTime birthTime = fileInfo.fileTime(QFile::FileBirthTime);
        QDateTime modifTime = fileInfo.fileTime(QFile::FileModificationTime);
        QDateTime accessTime = fileInfo.fileTime(QFile::FileAccessTime);
    
        if (QFile::exists((destination)))
        {
            QFile::remove(destination);
        }
    
        bool worked = QFile::copy(origin, destination);
    
        if (worked) {        
            // Destination is an .jpg file
            QFile d(destination);
            if(d.open(QFile::WriteOnly)) { // Set file size to 0 event if i comment setFileTime below
               // setFileTime return false if file is not opened 
                //d.setFileTime(accessTime, QFile::FileAccessTime);
                // d.setFileTime(modifTime, QFile::FileModificationTime);
                // d.setFileTime(birthTime, QFile::FileAccessTime);
                d.close();
                return true;
            } else {
                return  false;
            }
        } else {
            return false;
        }
    }
    
    

    Is then an other way to modify image m├ętadatas?


  • Qt Champions 2019

    @ClementD said in SetFileTime on an image, File::open set filesize to 0:

    when i try to open a ".jpg" file, the file's size is automatically set to 0.

    What do you expect? See https://doc.qt.io/qt-5/qiodevice.html#OpenModeFlag-enum



  • Hello @Christian-Ehrlicher , I want to copy a file keeping file times from the original. When i open the file, i do not want to modify it's content (only date)

    i also try to open it using QFile::WriteOnly | QFile::ExistingOnly flags or QFile::WriteOnly | QFile::Unbuffered, same issue



  • Problem solved using if(d.open(QFile::WriteOnly | QFile::Append)) to open th file


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