How to set the scope of QSettings to be application based.

[wladek]

Hi all,

I am using QSettings and have seen that one could set the applicationName and the organizationName for a QApplication, so that QSettings can be used as:

QSettings settings;

QSettings settings;

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and the setting will reside into the already set applicationName and organizationName.

My question here: is there a possibility to achieve something similar also with the Scope of the QSettings.
If i would just do QSettings settings; the Scope would be QSettings:UserScope and I need QSettings:SystemScope.

One solution would be to use this constructor:

QSettings settings(QSettings::SystemScope, QApplication::organizationName());

QSettings settings(QSettings::SystemScope, QApplication::organizationName());

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, but this involves more coding.

Is there any other better way to achieve this?

Thanks in advance,
Wladek

[Lykurg]

See the static function QSettings::setPath().

[Lykurg]

See the static function QSettings::setPath().

Ok, after a quick control look inside the documentation: Forget about that solution, I thought you can just swap the path, but it's not that easy.

So for avoiding typing all that parameters, you can define a global function returning a proper settings object. (Or define a macro.)

[wladek]

Hey Lykurg,

Thanks for your reply. I did try to define a macro like:

#define Settings QSettings(QSettings::SystemScope, QApplication::organizationName(), QApplication::applicationName());

#define Settings QSettings(QSettings::SystemScope, QApplication::organizationName(), QApplication::applicationName());

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But then when I would want to use it like:

QSettings settings = Settings;

QSettings settings = Settings;

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I would get the error:

QSettings::QSettings(const QSettings&)' is private

After checking with the QSettings source code i've seen that the copy constructor was disabled

Q_DISABLE_COPY(QSettings)

Q_DISABLE_COPY(QSettings)

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So, as a solution I defined my own custom class, SystemSettings which inherits QSettings, and in it's constructor just calls the proper QSettings's constructor.

class SystemSettings : public QSettings
{
public:
    SystemSettings()
        :QSettings(QSettings::SystemScope, QApplication::organizationName(), QApplication::applicationName()){};
};

class SystemSettings : public QSettings
{
public:
    SystemSettings()
        :QSettings(QSettings::SystemScope, QApplication::organizationName(), QApplication::applicationName()){};
};

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And, to be in the same side Qt is, i am also disabling my copy constructor:

private:
    Q_DISABLE_COPY(SystemSettings);

private:
    Q_DISABLE_COPY(SystemSettings);

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Would you suggest different?

Thanks,
Wladek

[Lykurg]

Yeah, great, I'm a fan of subclassing Haven't thought of that before, and that's the most elegant solution!