FAQ-1299 My application will not backup/restore properly. Do you have any tips or tricks?


FAQ-1299 My application will not backup/restore properly. Do you have any tips or tricks?

» Symbian OS » Developer Knowledgebase » FAQ-1299

Classification:	C++	Category:	Symbian Connect
Created:	08/03/2005	Modified:	09/05/2005
Number:	FAQ-1299
Platform:	Symbian OS v7.0s, Symbian OS v8.0, Symbian OS v8.0a, Symbian OS v8.0b, Symbian OS v8.1a, Symbian OS v8.1b, Symbian OS v9, Symbian OS v9.0

Question:
My application will not backup/restore properly. Do you have any tips or tricks?

Answer:
Pre-Symbian OS v9
Normally, backup/restore will send appropriate shutdown messages to your application to ensure a backup/restore can be successfully conducted. Your application may also be automatically restarted after this process, depending on the phone/software. Only slightly non-standard applications are likely to have problems - and in this case, you must manually subscribe your product with the backup/restore server. For releases before Symbian OS v9, you should do this using the relevant APIs in the CBaServBackupSession class - please see your specific SDK documentation for more details. For Symbian OS v9 onwards, you should register with the backup/restore server via the Publish & Subscribe framework - again, consult your SDK documentation for further details.

A real-world example: your product uses the Series 60 PhoneBookEngine component but hides its Window Group. The PhoneBookEngine (quite legitimately) opens a lock on the Contacts Database. However, when a backup commences, your Window Group cannot receive a shutdown message and hence the lock is not released and thus the contacts file cannot be backed up.

Symbian OS v9 onwards
Aside from the above advice about being responsive to the framework, from Symbian OS v9 you must explicitly register your application and data to be backed up. More details coming soon in the form of a technical paper on the Symbian Developer Network!