Resources for the stream are allocated at this time. Split streams share one set of stream buffers. This type of stream is used for interleaved data types. Once a stream is created of an interleaved data type (specified in the SPCB), another stream can use the stream handle of the first stream in the hstreamBuf parameter to indicate that it needs to share the set of buffers of the first stream. Each stream created must have a unique implicit event control block (EVCB). For NULL streams, both the hidSrc and the hidTgt must be the NULL stream handler ID (HID). Source and target devices can be specified using the DCBs for the respective stream handlers. Each stream handler can define a set of device control blocks that can be used at stream-creation time.