Introduction to EPOC OPL Development

Extending OPL

In addition to "basic" OPL there are two mechanism by which OPL can be extended, these are OPMs and OPXs. Symbian supply a number of OPMs and OPXs that are freely available from the developer web site. In addition, several are available from third parties, details on these are also available on the Symbian developers web site.

OPM

OPMs are simply OPL programs that have been built to deliver common functionality. They are loaded by the main OPL program and their functionality accessed as OPL procedures. OPMs are currently available to implement:

• the standard EPOC toolbar
• a range of buttons and other functionality

OPX

OPXs are C++ DLLs that provide access to core EPOC functionality not directly accessible through the basic OPL keywords. The functionality provided by OPXs simply adds a number of key words to OPL.

There are a wide range of OPXs available to provide access to system information, comms, agenda, contact files and more. A number of third parties have developed OPXs which also assist the development of more feature rich applications with multi-page dialogs and vector printing.

One note with OPXs. As these are written in C++ the OPX delivered for use on an EPOC device will not work on the emulator. To run them on the emulator it is necessary to get a WINS version. For all the Symbian supported OPXs the WINS version is delivered with the native EPOC version. For some of the third party ones you may need to approach the developer to get the WINS version.