NAME
        ReadChunkBytes -- read bytes from the current chunk into a buffer.
                          (V36)

   SYNOPSIS
        actual = ReadChunkBytes(iff, buf, numBytes);
        D0                      A0   A1   D0

        long readchunkbytes(struct iffhandle *, aptr buf, long);

   FUNCTION
        Reads the iffhandle stream into the buffer for the specified number
        of bytes. Reads are limited to the size of the current chunk and
        attempts to read past the end of the chunk will truncate. This
        function returns positive number of bytes read or a negative error
        code.

   INPUTS
        iff - pointer to iffhandle structure.
        buf - pointer to buffer area to receive data.
        numBytes - number of bytes to read.

   RESULT
        actual - (positive) number of bytes read if successful or a
                 (negative) IFFERR_#? error code if unsuccessful.

   SEE ALSO
        readchunkrecords(), parseiff(), writechunkbytes(),
        <libraries/iffparse.h>