Subscribing To Non-Edition Files

Using the Edition Manager, a subscriber can read data directly from

another document, such as an entire 'PICT' file, instead of subscribing to an

edition. This feature is for advanced applications that can set up bottleneck

procedures for reading. The Figure below shows a document that is subscribing

directly to a 'PICT' file.

For each application, the Edition Manager keeps a pointer to a bottleneck

function. The Edition Manager never opens or closes an edition container

directly. Instead, the Edition Manager calls the current edition opener. The

InitEditionPack function sets up the current system opener function.

To override the standard opener function, create an opener function that

contains the following parameters.

OSErr MyOpener (EditionOpenerVerb selector, EditionOpenerParamBlock

*pb);

Subscribing directly to a 'PICT' file

Your opener needs to know which formats the file contains and how the data is

supposed to be read or written.

The opener can allocate a handle or pointer to contain information such as file

reference numbers. This value is passed as ioRefNum to the I/O procedures.

The eoOpen and eoOpenNew edition opener verbs ( described in Calling an

Edition Opener Procedure below) return a pointer to a function to do the

actual reading and writing.

The following sections describe

• getting the current edition opener procedure

• setting an edition opener procedure

• calling an edition opener procedure

• opening and closing Editions

Getting the Current Edition Opener

When you want to get the current edition opener procedure, use the

The opener parameter returns the pointer to the current edition opener

procedure. A different current opener is kept for each application. One

application's opener is never called by another application.

Setting an Edition Opener

You can provide your own edition opener procedure. To do so, use the

Referenced by (4):