To get the external storage on Android I use
@ #ifdef Q_OS_ANDROID
but in iOS?
What external storage are you expecting on a iOS device ?
Can I store data in home dir as a unix system?
The data will be erase when the app will be upgrade as Android?
You should access storage only thru Qt official way: see QStandardPaths object.
More specifically: on these mobile OS there's a lot of strict restrictions on where you can write.
Use the suggestion of AlterX
Been doing some work on this today...
will only give you the internal sd card on certain devices, for example all the Samsung Tab varieties.
I did read somewhere that QStandardPaths may include an external storage location, later on down the line.