Function gnrc_pktbuf_mark

pub unsafe extern "C" fn gnrc_pktbuf_mark(
    pkt: *mut gnrc_pktsnip_t,
    size: size_t,
    type_: gnrc_nettype_t,
) -> *mut gnrc_pktsnip_t

@brief Marks the first @p size bytes in a received packet with a new packet snip that is appended to the packet.

Graphically this can be represented as follows:

Before                                    After
======                                    =====
                                                      (next)
 pkt->data                                 result->data <== pkt->data
 v                                         v                v
+--------------------------------+        +----------------+---------------+
+--------------------------------+        +----------------+---------------+
 \__________pkt->size___________/          \_result->size_/ \__pkt->size__/

If size == pkt->size then the resulting snip will point to NULL in its gnrc_pktsnip_t::data field and its gnrc_pktsnip_t::size field will be 0.

@pre @p pkt != NULL && @p size != 0

@param[in] pkt A received packet. @param[in] size The size of the new packet snip. @param[in] type The type of the new packet snip.

@note It’s not guaranteed that result->data points to the same address as the original pkt->data.

@return The new packet snip in @p pkt on success. @return NULL, if pkt == NULL or size == 0 or size > pkt->size or pkt->data == NULL. @return NULL, if no space is left in the packet buffer.