Qsettings does not differentiate between string and int values

[yaronkle]

OK, let me explain.

I am porting Windows code that calls RegQueryValueEx (for example, there are other API's).
RegQueryValueEx returns the correct type to the user, since that type is written correctly in Windows Registry (also in QSettings as long as you run it without stopping the process).

I have written a Linux implementation of RegQueryValueEx.

I can modify all the calls to RegQueryValueEx (which is a hassle).
Because this is a multiplatform project, I can't guarantee that another developer won't call RegQueryValueEx and rely on it to return the correct type.

[Santosh Reddy]

Don't mix up APIs. Either stick to Qt APIs on all platforms or use your custom (or legacy) on all platform.

[anda_skoa]

So if I understand correctly you are not actually creating a Qt API for something but you are backing a compatibility shim of sorts by Qt code, right?
And you shim function has to return a typed value or at least a type on request?

While that sounds very painful to maintain long term, you probably have reasons not to do a clean port.

As far as I can see you have to options:
1) use a backend that contains the type information just like the original API's backend does
2) use a type-less backend and try to find the closest type by trying potental conversion

Cheers,
_

[yaronkle]

That is correct for both questions!

What is a backend?
Are you referring to QSettings::SetIniCodec?

I have an idea, I have seen QT add quotes at one time to. I think it was when I played with QSringList.
Thinking of storing strings as QStringList of length 0. QVariant::type() will probably return the correct value.

[anda_skoa]

What is a backend?
Are you referring to QSettings::SetIniCodec?

No, QSettings would be one possible backend for storing values.

Other alternatives would be JSON, XML or some custom storage format, e.g. using QDataStream.
Even with QSettings as the backend, you could store the type as a subkey of the value.

Cheers,
_

[yaronkle]

I have a working solution which was simpler than expected.

When writing string values to the INI file, I append "\"STRING" to the string
When reading generic values. If the QVariant is a string without the above prefix I assume it's an int.
Works like a charm.

Many thanks to all of you!