> From: David Marchand [mailto:[email protected]] > Sent: Monday, 12 January 2026 08.59 > > Hello, > > On Mon, 12 Jan 2026 at 02:04, Stephen Hemminger > <[email protected]> wrote: > > #### Warning (Minor) > > > > **Implicit boolean comparison:** The `RTE_MBUF_DIRECT(mbuf)` macro > returns an integer-like value (0 or non-zero). Per DPDK guidelines, > explicit comparison with zero is preferred for integers: > > > > ```c > > // Suggested (strict interpretation): > > if (RTE_MBUF_DIRECT(mbuf) != 0 && mbuf->pool == umem->mb_pool) { > > ``` > > > > However, this macro is semantically boolean and is commonly used in > direct form throughout DPDK. This is a stylistic preference, not a > blocking issue. > > All callers in DPDK are using this macro as a boolean, and I found no > opensource project doing differently. > I would either fix the macro or change nothing at all.
The macro's return type is int, not bool. However, it is defined as "!something()", so it returns only 0 or 1: https://elixir.bootlin.com/dpdk/v25.11/source/lib/mbuf/rte_mbuf_core.h#L732 Also in DPDK 24.11: https://elixir.bootlin.com/dpdk/v24.11/source/lib/mbuf/rte_mbuf_core.h#L715 And in DPDK 17.11: https://elixir.bootlin.com/dpdk/v17.11/source/lib/librte_mbuf/rte_mbuf.h#L714 Haven't gone further back in history. :-)
