NAME
        EntryHandler -- add an entry handler to the iffhandle context. (v36)

   SYNOPSIS
        error = EntryHandler(iff, type, id, position, handler, object);
        D0                   A0   D0    D1  D2        A1       A2

        long entryhandler(struct iffhandle *, long, long, long,
                          struct hook *, aptr);

   FUNCTION
        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:

        Return value            Result
        ------------            ------
        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
                                you supplied. This is how errors should be
                                returned.

   INPUTS
        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.

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

   BUGS
        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.

   SEE ALSO
        exithandler(), storelocalitem(), storeitemincontext(),
        <utility/hooks.h>, <libraries/iffparse.h>