PluginDemo

Short:        V1.1 plugin demo using LoadSeg
Author:       Dirk Stoecker
Uploader:     stoecker epost de (Dirk Stoecker)
Type:         dev/c
Architecture: m68k-amigaos

This example code shows how to make a plugin system using the LoadSeg()
funtion. Other methods use the library system, which I think is a misuse
of the system for shared libraries.

This demo shows lots of methods used in development of the XAD library
system, so if something is unclear, read the docs of XAD.

Supported features:
- Plugins may be internal and external. This allows compact executables
  with plugin support (but does not require external plugins).
- Internal plugins get an unique ID and can be overwritten by external
  plugins.
- Multiple plugins in one file. This allows to reuse common code.
- Enforces version strings for the plugins to make the C:Version
  command work.
- Versioning system to allow up- and downwards compatibility.

How to compile:
The file master.c is a normal C source code and can be compiled with
any compiler without problems.

The plugin files creation consist of three steps:
a) The file exterheader.c is compiled to an object file. To get this
   file the linking option must be turned of and data modell must be
   large.
b) The plugin source must be compiled without linking and in large
   data mode as well.
   NOTE: Using standard ANSI-C I/O-functions is not possible normally,
   as no startup-code is used (this is a plugin!). Also DOSBase or
   any other library base is not opened automatically. Either the
   master supplies these, or the libraries must be opened in the plugin
   from scratch (using AbsExecBase as starting point).
c) Linking the two files together, where the extheader object is
   the first one and the plugin file the second.

Makefiles are supplied for SAS-C and VBCC. Both files will work with
GNU make and smake (except clean and cleanall targets, which only work
with smake).

NOTE: The functions in this example use the stack for argument passing.
When creating public plugins it may be better to use registers.

If you can submit adjustments and fixes feel free to send these. Feel
free to use this source for own projects.

History:
  1.0  first version
  1.1  fixed for GCC, Thanks Gunther Nikl and Daniel Allsopp for help

Please contact me:

*********************************************************************
* snail-mail:                  * e-mail:                            *
*   Dirk Stoecker              *   stoecker@epost.de                *
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Following is my PGP signature for the corresponding LhA-File.
Use ' pgpv PluginDemo.readme -o PluginDemo.lha ' to check it.
Key fingerprint: B9 F2 3A 1A 29 02 75 16  6A C6 5B 7D 5E F6 16 CF.
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