NAME
    PushChunk -- Push a new context node on the context stack.

SYNOPSIS
    error = PushChunk (iff, type, id, size)
     d0                a0    d0   d1   d2

    LONG             error;
    struct iffhandle *iff;
    LONG             type, id, size;

FUNCTION
    Pushes a new context node on the context stack by reading it from the
    stream if this is a read file, or by creating it from the passed
    parameters if this is a write file.  Normally this function is only
    called in write mode, where the type and id codes specify the new
    chunk to create.  If this is a leaf chunk, i.e. a local chunk inside
    a FORM or PROP chunk, then the type argument is ignored.  If the size
    is specified then the chunk writing functions will enforce this size.
    If the size is given as IFFSIZE_UNKNOWN, the chunk will expand to
    accommodate whatever is written into it.

INPUTS
    iff     - pointer to iffhandle struct.
    type    - chunk type specifier (ex. ILBM) (ignored for read mode or
              leaf chunks).
    id      - chunk id specifier (ex. CMAP) (ignored for read mode).
    size    - size of the chunk to create or IFFSIZE_UNKNOWN (ignored for
              read mode).

RESULT
    error   - 0 if successful or an IFFERR_#? error code if not
              successful.

EXAMPLE

NOTES

BUGS

SEE ALSO
    popchunk(), writechunkrecords(), writechunkbytes()