From f5c91707482499ad12b09799fa4788fab587c09c Mon Sep 17 00:00:00 2001 From: Dominik Loidolt Date: Mon, 8 Jun 2026 14:44:18 +0200 Subject: [PATCH 1/2] compat/posix.h: enable UNUSED warning messages for Clang Use a dedicated Clang version check for the UNUSED macro. Commit 7c07f36ad2 (git-compat-util.h: GCC deprecated message arg only in GCC 4.5+, 2022-10-05) restricted use of the deprecated attribute's message argument in the UNUSED macro to GCC 4.5 or newer. Clang identifies itself as GNUC 4.2.1 for compatibility, so GIT_GNUC_PREREQ(4, 5) does not detect whether Clang supports the deprecated("...") form. Add GIT_CLANG_PREREQ() macro and use it to enable the UNUSED warning message for Clang 2.9 and newer. Signed-off-by: Dominik Loidolt Signed-off-by: Junio C Hamano --- compat/posix.h | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/compat/posix.h b/compat/posix.h index faaae1b655..ffdfd91c7b 100644 --- a/compat/posix.h +++ b/compat/posix.h @@ -22,6 +22,15 @@ #define GIT_GNUC_PREREQ(maj, min) 0 #endif +/* Similar for Clang. */ +#if defined(__clang__) && defined(__clang_minor__) && defined(__clang_major__) +# define GIT_CLANG_PREREQ(maj, min) \ + ((__clang_major__ > (maj)) || \ + (__clang_major__ == (maj) && __clang_minor__ >= (min))) +#else +# define GIT_CLANG_PREREQ(maj, min) 0 +#endif + /* * UNUSED marks a function parameter that is always unused. It also * can be used to annotate a function, a variable, or a type that is @@ -35,7 +44,7 @@ * When a parameter may be used or unused, depending on conditional * compilation, consider using MAYBE_UNUSED instead. */ -#if GIT_GNUC_PREREQ(4, 5) +#if GIT_GNUC_PREREQ(4, 5) || GIT_CLANG_PREREQ(2, 9) #define UNUSED __attribute__((unused)) \ __attribute__((deprecated ("parameter declared as UNUSED"))) #elif defined(__GNUC__) From dd74b62c25e8a98c54b9416838237b878d84c768 Mon Sep 17 00:00:00 2001 From: Dominik Loidolt Date: Mon, 8 Jun 2026 14:44:19 +0200 Subject: [PATCH 2/2] compat/posix.h: simplify GIT_GNUC_PREREQ() comparison Replace the glibc-style bit-shift version comparison with an explicit major/minor comparison. This is easier to read and is consistent with the format already used by GIT_CLANG_PREREQ() and many BSD headers. This has no runtime impact, as the macro is evaluated at compile time. It is also more future-proof, as it no longer assumes that GCC version components stay below 65536. Signed-off-by: Dominik Loidolt Signed-off-by: Junio C Hamano --- compat/posix.h | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/compat/posix.h b/compat/posix.h index ffdfd91c7b..deefc43f28 100644 --- a/compat/posix.h +++ b/compat/posix.h @@ -4,22 +4,24 @@ #define _FILE_OFFSET_BITS 64 /* - * Derived from Linux "Features Test Macro" header - * Convenience macros to test the versions of gcc (or - * a compatible compiler). + * Convenience macros to test the versions of GCC (or a compatible compiler). * Use them like this: * #if GIT_GNUC_PREREQ (2,8) - * ... code requiring gcc 2.8 or later ... + * ... code requiring GCC 2.8 or later ... * #endif * + * Note that Clang and other compilers define __GNUC__ for compatibility; use + * GIT_CLANG_PREREQ() to check for specific Clang versions. + * * This macro of course is not part of POSIX, but we need it for the UNUSED * macro which is used by some of our POSIX compatibility wrappers. -*/ + */ #if defined(__GNUC__) && defined(__GNUC_MINOR__) # define GIT_GNUC_PREREQ(maj, min) \ - ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min)) + ((__GNUC__ > (maj)) || \ + (__GNUC__ == (maj) && __GNUC_MINOR__ >= (min))) #else - #define GIT_GNUC_PREREQ(maj, min) 0 +# define GIT_GNUC_PREREQ(maj, min) 0 #endif /* Similar for Clang. */