Symbian OS Tips, Tricks & Code

December 2006: example application updated from UIQ 3 beta SDK to final UIQ 3 SDK

This is an example of building and using a dynamic library in your UIQ 3 applications. We've received feedback that some developers were experiencing problems when installing this sort of application on the P990 smartphone and we hope that the information below helps.

Download example application>>

Here is how you should build this application:

Build for emulator:

• From command line in folder \MyDllApp\group:
  • bldmake bldfiles
  • abld build winscw udeb
  • abld freeze winscw
  • abld build winscw udeb
• In Codewarrior:
  • import and build TestDLL first
  • import, build and start HelloWorld

Build for Sony Ericsson P990 smartphone:

• From command line in folder \MyDllApp\group:
  • bldmake bldfiles
  • abld build gcce urel
  • abld freeze gcce
  • abld build gcce urel
  • makesis HelloWorld_gcce.pkg

Important things to remember and check:

• » UIQ 3 SDK » Symbian OS v9.1 » Symbian OS Tools And Utilities » Build tools guide » How to build DLLs
• If you have some problems with the application, check "Troubleshooting building and installing P990 UIQ 3 applications" for clues about what could be wrong. Try commenting out most functionality to find out what causes problems.
• Use proper UIDs received from Symbian Signed.
• If you experience problems with the keyword EXPORTUNFROZEN, try this workaround to freeze the DLL, and then build for gcce. The keyword EXPORTUNFROZEN should be removed from the mmp file.
• Important issues related to capabilities for both application and library:
  • Dll needs to have at least the same capabilities as the application that tries to use it.
  • Dll need to have as many capabilities as possible so applications can use it: "Shared libraries that export a static interface will need to have capabilities such that all its users may load them".
• Platform Security information from Symbian – read pdf here>>

Rule 2: A process cannot load a DLL with less capabilities than itself…DLL
capabilities do only reflect a level of trust…DLL
capabilities do not authorise anything…
DLL code runs at process' capabilities level…
DLL can have more capabilities than process

• You can test this using this example (capability NetworkServices used by this application does not require the application to be signed - at installation, the user will be asked for permission):
  • As the application is built initially, neither "exe" nor "dll" uses capabilities. The application can be installed and started on the P990 smartphone.
  • If you add a capability to an "exe" only (simply uncomment "CAPABILITY" in .mmp file), rebuild and install on the P990, you'll get the error: "Application couldn't be started".
  • If you add a capability also to the "dll", rebuild and install the application, you can see that it will start without any problems.

More information:

• » UIQ 3 SDK » Symbian OS v9.1 » Symbian OS Tools And Utilities » Build tools guide » How to build DLLs
• February 2006 Tips, Tricks & Code article "Troubleshooting building and installing P990 UIQ 3 applications">>
• Platform Security information from Symbian>>