View source for How to program for the WPS

The WPS is based on SOM the [http://en.wikipedia.org/wiki/System_Object_Model System Object Model]. SOM allows access objects across various processes (including processes on remote machine) via [[DSOM]] classes, an implementation of an ORB compatible with an older (version 1.1) CORBA specification (remember SOM wasn't updated for quite a while. At hobbes there is a newer SOM implementation, but some people have reported problems with it).
There's a lot of fuzz about how advanced the WPS is because it uses CORBA etc. bla bla. In fact, most of the features of the WPS don't need a fully CORBA compliant ORB and, more importantly, don't use it. While Distributed SOM (DSOM) comes with OS/2, the WPS seem to use only local SOM.

Note: It is possible to use DSOM for WPS objects access. You need to start WPS DSOM server first. 

While it's possible to query, load, unload and replace SOM classes on demand during program execution, the WPS usually builds its class tree during initialization. Thus class replacement requires a WPS restart. Note that the adding of classes can still be done without a restart.
Saying this doesn't mean you can never replace a class during runtime. It's always possible to bend the borders with some serious hacking but there's no general API for that.

===Prerequisites===

* SOM compiler - Contained in the OS/2 toolkit which comes with your commercial compiler or eCS. 
 Or at http://hobbes.nmsu.edu/pub/os2/dev/wps/somobjtk.zip 
 or at http://hobbes.nmsu.edu/pub/os2/dev/wps/opendc12.zip
* C compiler - Visual Age 3.08
 Or any C/C++ compiler. Open Watcom was tested for easy tasks and all worked fine. There was an article
 in a german magazine quite a while ago with an example using EMX.

* For other programming languages (Pascal,... ) you need to write an [[emitter]] for the [[SOM Compiler]] which creates the necessary binding files.

===Programming===

* [[Short overview]] how WPS programming works in general.
* [[Tutorial]] for a simple WPS class.
* [http://wpstk.netlabs.org Workplace Shell Toolkit]<br>(C library to ease PM and WPS programming, supporting GNU compiler of emx V0.9d, IBM C Set /2 and VAC 3.08). Not SOM-based.

[[Category:SOM Articles]]