· WimpExtension needs to know which task is calling it. It is told when you call WimpExt_Initialise or WimpExt_Action, but calls to Wimp_Poll may change it (as other tasks call it). If you have not called WimpExt_Initialise or WimpExt_Action since the last Wimp_Poll therefore, you should call WimpExt_CurrentTask to tell WimpExtension your task handle.
· In general, all strings are control-terminated, ie. they may not containany characters less than 32, which are treated as terminators.
· Some features of WimpExtension are controlled by the validation strings of icons. To have a validation string, the icon must be indirected text (plus sprite if you want). (If you don't want text, make it text, just don't put any text in it.) Validation commands are separated by semicolons; you can put as many as you want on a single icon. You shouldn't use the same command twice, unless you are specifically told you can. (The behaviour is undefined if you do - ie. different versions of WimpExtension may do different things.)
· Since it claims workspace for tasks it knows about, WimpExtension MUST know when a task closes down. You should therefore, always call WimpExt_CloseDown before your task exits. To catch any unavoidable slips (eg. Address Exceptions in BASIC) WimpExtension initialises a module task which will call WimpExt_CloseDown for any tasks that exit. You must not rely on this, though.
· All SWIs corrupt R0, even if they are not using it to return a result.
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