EntryHandler

add an entry handler to the IFFHandle context. (V36)

Installs an entry handler vector for a specific type of chunk into the context for the given IFFHandle structure. Type and id are the longword identifiers for the chunk to handle. The handler is a client- supplied standard Hook structure, properly initialized. position tells where to put the handler in the context. The handler will be called whenever the parser enters a chunk of the given type, so the IFF stream will be positioned to read the first data byte in the chunk. The handler will execute in the same context as whoever called ParseIFF(). The handler will be called (through the hook) with the following arguments:

A0

the Hook pointer you passed.

A2

the 'object' pointer you passed.

A1

pointer to a LONG containing the value IFFCMD_ENTRY.

The error code your call-back routine returns will affect the parser in three different ways:

0

Normal success; ParseIFF() will continue through the file.

IFF_RETURN2CLIENT

ParseIFF() will stop and return the value 0. (StopChunk() is internally implemented using this return value.)

Any other value - ParseIFF() will stop and return the value

iff

pointer to IFFHandle structure.

type

type code for chunk to handle (ex. "ILBM").

id

ID code for chunk to handle (ex. "CMAP").

position- local context item position. One of the IFFSLI_#? codes.

handler

pointer to Hook structure.

object

a client-defined pointer which is passed in A2 during call- back.

error

0 if successful or an IFFERR_#? error code if unsuccessful.

Returning the values IFFERR_EOF or IFFERR_EOC from the call-back routine *may* confuse the parser.

There is no way to explicitly remove a handler once installed. However, by installing a do-nothing handler using IFFSLI_TOP, previous handlers will be overridden until the context expires.

ExitHandler(), StoreLocalItem(), StoreItemInContext(), <utility/hooks.h>, <libraries/iffparse.h>