Hi, On Fri, Nov 07, 2025 at 05:05:11PM +0100, Peter Eisentraut wrote: > On 07.11.25 16:03, Bertrand Drouvot wrote: > > +/* > > + * Mark a declaration as deprecated with a custom message. The compiler > > will > > + * emit a warning when the deprecated entity is used. > > + */ > > +#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202311L || \ > > +defined(__cplusplus) && __cplusplus >= 201402L > > This could use some parentheses to disambiguate the && and ||. > > Also the second line could be indented (or just put it on one line).
Agree that it could be more clear. Done that way in the attached (using only one line as it looks more readable). > > +#define pg_attribute_deprecated(msg) [[deprecated(msg)]] > > +#elif defined(__GNUC__) || defined(__clang__) > > The __clang__ part is not needed, because clang defines __GNUC__ also. Good catch, thanks! Fixed in the attach. Regards, -- Bertrand Drouvot PostgreSQL Contributors Team RDS Open Source Databases Amazon Web Services: https://aws.amazon.com
>From 5ce58b18992bbaf98eb4d0d0b9cf50e25a191aee Mon Sep 17 00:00:00 2001 From: Bertrand Drouvot <[email protected]> Date: Fri, 7 Nov 2025 14:18:31 +0000 Subject: [PATCH v8] Introduce pg_attribute_deprecated() and deprecate XLogRecPtrIsInvalid() This commit creates a new macro pg_attribute_deprecated() to mark a declaration as deprecated with a custom message. The compiler will emit a warning when the deprecated entity is used. Then it makes use of this new macro to emit a deprecated message about XLogRecPtrIsInvalid() as of version 21 (no need to be more conservative and wait until version 24 as XLogRecPtrIsValid() has been added in back branches). --- src/include/access/xlogdefs.h | 17 +++++++++++++++++ src/include/c.h | 14 ++++++++++++++ 2 files changed, 31 insertions(+) 48.1% src/include/access/ 51.8% src/include/ diff --git a/src/include/access/xlogdefs.h b/src/include/access/xlogdefs.h index 5f07e57c832..1ed8f1b413e 100644 --- a/src/include/access/xlogdefs.h +++ b/src/include/access/xlogdefs.h @@ -27,6 +27,23 @@ typedef uint64 XLogRecPtr; */ #define InvalidXLogRecPtr 0 #define XLogRecPtrIsValid(r) ((r) != InvalidXLogRecPtr) + +/* + * New code should use XLogRecPtrIsValid() instead of XLogRecPtrIsInvalid() + * for consistency with the affirmative form of macros used for other datatypes + * and to avoid awkward double negative. + * This function is retained for convenience of third-party code but is/will be + * deprecated as of version 21. + */ +#if PG_VERSION_NUM >= 210000 +pg_attribute_deprecated("use XLogRecPtrIsValid() instead") +#endif +static inline bool +XLogRecPtrIsInvalid(XLogRecPtr ptr) +{ + return ptr == InvalidXLogRecPtr; +} + #define XLogRecPtrIsInvalid(r) ((r) == InvalidXLogRecPtr) /* diff --git a/src/include/c.h b/src/include/c.h index 757dfff4782..053635e984c 100644 --- a/src/include/c.h +++ b/src/include/c.h @@ -227,6 +227,20 @@ #define PG_USED_FOR_ASSERTS_ONLY pg_attribute_unused() #endif +/* + * Mark a declaration as deprecated with a custom message. The compiler will + * emit a warning when the deprecated entity is used. + */ +#if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202311L) || (defined(__cplusplus) && __cplusplus >= 201402L) +#define pg_attribute_deprecated(msg) [[deprecated(msg)]] +#elif defined(__GNUC__) +#define pg_attribute_deprecated(msg) __attribute__((deprecated(msg))) +#elif defined(_MSC_VER) +#define pg_attribute_deprecated(msg) __declspec(deprecated(msg)) +#else +#define pg_attribute_deprecated(msg) +#endif + /* GCC supports format attributes */ #if defined(__GNUC__) #define pg_attribute_format_arg(a) __attribute__((format_arg(a))) -- 2.34.1
