From: Stephen Hemminger <stephen@networkplumber.org>
To: scott.k.mitch1@gmail.com
Cc: dev@dpdk.org, mb@smartsharesystems.com
Subject: Re: [PATCH v3 v3 1/2] eal: RTE_PTR_ADD/SUB char* for compiler optimizations
Date: Sun, 11 Jan 2026 11:07:41 -0800 [thread overview]
Message-ID: <20260111110741.03cca1e4@phoenix.local> (raw)
In-Reply-To: <20260111160059.293-2-scott.k.mitch1@gmail.com>
On Sun, 11 Jan 2026 11:00:58 -0500
scott.k.mitch1@gmail.com wrote:
> +#define RTE_PTR_ADD(ptr, x) \
> + (__extension__ ({ \
> + /* Diagnostics suppressed for internal macro operations only. \
> + * Compiler type-checks all _Generic branches even when unselected, \
> + * triggering warnings with no external impact. */ \
> + __rte_diagnostic_push \
> + __rte_diagnostic_ignored_wcast_qual \
> + /* Uses uintptr_t arithmetic for integer types (API compatibility), \
> + * and char* arithmetic for pointer types (enables optimization). */ \
> + __auto_type _ptr_result = _Generic((ptr), \
NAK
No ignoring cast qualifiers. Is this just to preserve const?
DPDK does not guarantee API compatibility across versions, only ABI.
Why not clarify the code by using inline?
static inline void *__rte_ptr_offset(void *ptr, long delta)
{
return (char *)ptr + delta;
}
#define RTE_PTR_ADD(ptr, x) __rte_ptr_offset(ptr, (long)(x))
#define RTE_PTR_SUB(ptr, x) __rte_ptr_offset(ptr, -(long)(x))
What about RTE_PTR_SUB() and RTE_PTR_DIFF()?
next prev parent reply other threads:[~2026-01-11 19:07 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-11 16:00 [PATCH v3 0/2] " scott.k.mitch1
2026-01-11 16:00 ` [PATCH v3 v3 1/2] " scott.k.mitch1
2026-01-11 19:07 ` Stephen Hemminger [this message]
2026-01-11 16:00 ` [PATCH v3 v3 2/2] mailmap: add Scott Mitchell scott.k.mitch1
2026-01-12 0:06 ` Morten Brørup
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