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Adobe Acrobat SDK
Developing Plug-ins and Applications
The following diagram shows the relationship between Adobe Reader or Acrobat, other plug-ins, and HFTs.
Plug-ins must use the
plug-in requests an HFT by its name and version number. An HFT is imported during plug-in initialization.
For information, see
When a plug-in invokes a method in Adobe Reader, Acrobat, or another plug-in, the function pointer at the
appropriate location in the appropriate HFT is dereferenced and executed. Macros in the Acrobat SDK's
header files hide this functionality, so that plug-ins contain only what appear to be normal function calls.
Each HFT is serviced by an HFT server. The HFT server is responsible for handling requests to obtain or
destroy its HFT. As part of its responsibility to handle requests, an HFT server can choose to support
multiple versions of the HFT. These versions generally correspond to versions of Acrobat, Adobe Reader or
the plug-in that exposes the HFT.
The ability to provide more than one version of an HFT improves backward-compatibility by allowing
existing plug-ins to continue to work when new versions of Acrobat or Adobe Reader (or other plug-ins
whose HFTs they use) become available. It is expected that HFT versions typically will differ only in the
number, not the order, of methods they contain.
Exporting host function tables
You can use the Acrobat core API to export HFTs that result in a plug-in's methods being available to other
plug-ins. To export an HFT, perform the following tasks:
1. Create the HFT methods that you want to make available to other plug-ins.
2. Create HFT method definitions.
3. Create HFT callback functions.
4. Create new HFTs.
Note:
The remaining parts of this section examine each step in detail.
Acrobat
application
ASExtensionMgrGetHFT
"Importing HFTs and registering for notifications" on page
Plug-in
HFTs
Plug-in
method to import each HFT they intend to use. A
Working with Host Function Tables
Exporting host function tables
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