The clipboard
IFF provides a data sharing standard. In conjunction with that, the Amiga's clipboard device provides a place to store and retrieve that data. It does this by caching data to RAM and automatically spooling the data to disk if necessary.
The clipboard allows the exchange of data dynamically between your application and another.
The clipboard is the recommended storage device for cut-and-paste operations and it's the best place to store data which is meant to be quickly moved between two applications that are running simultaneously. It also provides a solid metaphor in keeping with the Workbench.
Use IFF
All data written to the clipboard must be written in the IFF format. For most applications the data will be one of two types: graphics or text. For graphic clips use the ILBM form of IFF. For text clips use the FTXT form of IFF.
When reading from the clipboard, never blindly read the data assuming, for instance, that the clip contains FTXT with a CHRS as the first and only chunk. Remember, the user may have been switching between many applications and may even have made a mistake in the cut-and-paste operation.
Storage Concerns
When storing data in the clipboard, it is acceptable to write different representations of the same data. For instance, in a music application when the user cuts a bar of music, the application can write the information in three ways. The music itself could be saved in a SMUS form; the lyrics could be saved separately in an FTXT form; and a picture of the notation could be saved in an ILBM form. This type of multiple clip should be contained within a CAT "wrapper" form. Use CAT CLIP as the global form name.
Unit Selection
The clipboard device allows for the selection of units ranging from zero to 255. By default, your application should always use clipboard unit zero for interactive cut, copy and paste operations. Provide a means, however, for the user to specify a different unit number.