diff options
Diffstat (limited to 'gnulib-m4/gnulib-common.m4')
| -rw-r--r-- | gnulib-m4/gnulib-common.m4 | 462 |
1 files changed, 400 insertions, 62 deletions
diff --git a/gnulib-m4/gnulib-common.m4 b/gnulib-m4/gnulib-common.m4 index d8d0904f..134bfba2 100644 --- a/gnulib-m4/gnulib-common.m4 +++ b/gnulib-m4/gnulib-common.m4 @@ -1,8 +1,10 @@ -# gnulib-common.m4 serial 92 -dnl Copyright (C) 2007-2024 Free Software Foundation, Inc. +# gnulib-common.m4 +# serial 113 +dnl Copyright (C) 2007-2025 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, dnl with or without modifications, as long as this notice is preserved. +dnl This file is offered as-is, without any warranty. AC_PREREQ([2.62]) @@ -19,43 +21,61 @@ AC_DEFUN([gl_COMMON_BODY], [ [/* Witness that <config.h> has been included. */ #define _GL_CONFIG_H_INCLUDED 1 ]) + dnl Avoid warnings from gcc -Wtrailing-whitespace. + dnl This is a temporary workaround until Autoconf fixes it. + dnl Test case: + dnl empty1=; empty2=; AC_DEFINE_UNQUOTED([FOO], [$empty1$empty2], [...]) + dnl should produce "#define FOO /**/", not "#define FOO ". + AH_TOP([#if defined __GNUC__ && __GNUC__ >= 15 && !defined __clang__ +# pragma GCC diagnostic push +# pragma GCC diagnostic ignored "-Wtrailing-whitespace" +#endif +]) + AH_BOTTOM([#if defined __GNUC__ && __GNUC__ >= 15 && !defined __clang__ +# pragma GCC diagnostic pop +#endif +]) AH_VERBATIM([_GL_GNUC_PREREQ], -[/* True if the compiler says it groks GNU C version MAJOR.MINOR. */ -#if defined __GNUC__ && defined __GNUC_MINOR__ +[/* True if the compiler says it groks GNU C version MAJOR.MINOR. + Except that + - clang groks GNU C 4.2, even on Windows, where it does not define + __GNUC__. + - The OpenMandriva-modified clang compiler pretends that it groks + GNU C version 13.1, but it doesn't: It does not support + __attribute__ ((__malloc__ (f, i))), nor does it support + __attribute__ ((__warning__ (message))) on a function redeclaration. + - Users can make clang lie as well, through the -fgnuc-version option. */ +#if defined __GNUC__ && defined __GNUC_MINOR__ && !defined __clang__ # define _GL_GNUC_PREREQ(major, minor) \ ((major) < __GNUC__ + ((minor) <= __GNUC_MINOR__)) +#elif defined __clang__ + /* clang really only groks GNU C 4.2. */ +# define _GL_GNUC_PREREQ(major, minor) \ + ((major) < 4 + ((minor) <= 2)) #else # define _GL_GNUC_PREREQ(major, minor) 0 #endif ]) AH_VERBATIM([_Noreturn], -[/* The _Noreturn keyword of C11. */ +[/* The _Noreturn keyword of C11. + Do not use [[noreturn]], because with it the syntax + extern _Noreturn void func (...); + would not be valid; such a declaration would be valid only with 'extern' + and '_Noreturn' swapped, or without the 'extern' keyword. However, some + AIX system header files and several gnulib header files use precisely + this syntax with 'extern'. So even though C23 deprecates _Noreturn, + it is currently more portable to prefer it to [[noreturn]]. + + Also, do not try to work around LLVM bug 59792 (clang 15 or earlier). + This rare bug can be worked around by compiling with 'clang -D_Noreturn=', + though the workaround may generate many false-alarm warnings. */ #ifndef _Noreturn -# if (defined __cplusplus \ - && ((201103 <= __cplusplus && !(__GNUC__ == 4 && __GNUC_MINOR__ == 7)) \ - || (defined _MSC_VER && 1900 <= _MSC_VER)) \ - && 0) - /* [[noreturn]] is not practically usable, because with it the syntax - extern _Noreturn void func (...); - would not be valid; such a declaration would only be valid with 'extern' - and '_Noreturn' swapped, or without the 'extern' keyword. However, some - AIX system header files and several gnulib header files use precisely - this syntax with 'extern'. */ -# define _Noreturn [[noreturn]] -# elif (defined __clang__ && __clang_major__ < 16 \ - && defined _GL_WORK_AROUND_LLVM_BUG_59792) - /* Compile with -D_GL_WORK_AROUND_LLVM_BUG_59792 to work around - that rare LLVM bug, though you may get many false-alarm warnings. */ -# define _Noreturn -# elif ((!defined __cplusplus || defined __clang__) \ - && (201112 <= (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) \ - || (!defined __STRICT_ANSI__ \ - && (_GL_GNUC_PREREQ (4, 7) \ - || (defined __apple_build_version__ \ - ? 6000000 <= __apple_build_version__ \ - : 3 < __clang_major__ + (5 <= __clang_minor__)))))) +# if ((!defined __cplusplus || defined __clang__) \ + && (201112 <= (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0))) /* _Noreturn works as-is. */ # elif _GL_GNUC_PREREQ (2, 8) || defined __clang__ || 0x5110 <= __SUNPRO_C + /* Prefer __attribute__ ((__noreturn__)) to plain _Noreturn even if the + latter works, as 'gcc -std=gnu99 -Wpedantic' warns about _Noreturn. */ # define _Noreturn __attribute__ ((__noreturn__)) # elif 1200 <= (defined _MSC_VER ? _MSC_VER : 0) # define _Noreturn __declspec (noreturn) @@ -89,6 +109,9 @@ AC_DEFUN([gl_COMMON_BODY], [ # define _GL_HAS_ATTRIBUTE(attr) __has_attribute (__##attr##__) # else # define _GL_HAS_ATTRIBUTE(attr) _GL_ATTR_##attr +/* The following lines list the first GCC version that supports the attribute. + Although the lines are not used in GCC 5 and later (as GCC 5 introduced + __has_attribute support), list GCC versions 5+ anyway for completeness. */ # define _GL_ATTR_alloc_size _GL_GNUC_PREREQ (4, 3) # define _GL_ATTR_always_inline _GL_GNUC_PREREQ (3, 2) # define _GL_ATTR_artificial _GL_GNUC_PREREQ (4, 3) @@ -109,12 +132,15 @@ AC_DEFUN([gl_COMMON_BODY], [ # endif # define _GL_ATTR_noinline _GL_GNUC_PREREQ (3, 1) # define _GL_ATTR_nonnull _GL_GNUC_PREREQ (3, 3) +# define _GL_ATTR_nonnull_if_nonzero _GL_GNUC_PREREQ (15, 1) # define _GL_ATTR_nonstring _GL_GNUC_PREREQ (8, 0) # define _GL_ATTR_nothrow _GL_GNUC_PREREQ (3, 3) # define _GL_ATTR_packed _GL_GNUC_PREREQ (2, 7) # define _GL_ATTR_pure _GL_GNUC_PREREQ (2, 96) +# define _GL_ATTR_reproducible _GL_GNUC_PREREQ (15, 1) # define _GL_ATTR_returns_nonnull _GL_GNUC_PREREQ (4, 9) # define _GL_ATTR_sentinel _GL_GNUC_PREREQ (4, 0) +# define _GL_ATTR_unsequenced _GL_GNUC_PREREQ (15, 1) # define _GL_ATTR_unused _GL_GNUC_PREREQ (2, 7) # define _GL_ATTR_warn_unused_result _GL_GNUC_PREREQ (3, 4) # endif @@ -130,6 +156,23 @@ AC_DEFUN([gl_COMMON_BODY], [ # define _GL_HAVE___HAS_C_ATTRIBUTE 0 #endif +/* Attributes in bracket syntax [[...]] vs. attributes in __attribute__((...)) + syntax, in function declarations. There are two problems here. + (Last tested with gcc/g++ 14 and clang/clang++ 18.) + + 1) We want that the _GL_ATTRIBUTE_* can be cumulated on the same declaration + in any order. + =========================== foo.c = foo.cc =========================== + __attribute__ ((__deprecated__)) [[__nodiscard__]] int bar1 (int); + [[__nodiscard__]] __attribute__ ((__deprecated__)) int bar2 (int); + ====================================================================== + This gives a syntax error + - in C mode with gcc + <https://gcc.gnu.org/PR108796>, and + - in C++ mode with clang++ version < 16, and + - in C++ mode, inside extern "C" {}, still in newer clang++ versions + <https://github.com/llvm/llvm-project/issues/101990>. + */ /* Define if, in a function declaration, the attributes in bracket syntax [[...]] must come before the attributes in __attribute__((...)) syntax. If this is defined, it is best to avoid the bracket syntax, so that the @@ -144,6 +187,176 @@ AC_DEFUN([gl_COMMON_BODY], [ # define _GL_BRACKET_BEFORE_ATTRIBUTE 1 # endif #endif +/* + 2) We want that the _GL_ATTRIBUTE_* can be placed in a declaration + - without 'extern', in C as well as in C++, + - with 'extern', in C, + - with 'extern "C"', in C++ + in the same position. That is, we don't want to be forced to use a + macro which arranges for the attribute to come before 'extern' in + one case and after 'extern' in the other case, because such a macro + would make the source code of .h files pretty ugly. + =========================== foo.c = foo.cc =========================== + #ifdef __cplusplus + # define CC "C" + #else + # define CC + #endif + + #define ND [[__nodiscard__]] + #define WUR __attribute__((__warn_unused_result__)) + + #ifdef __cplusplus + extern "C" { + #endif + // gcc clang g++ clang++ + + ND int foo (int); + int ND foo (int); // warn error warn error + int foo ND (int); + int foo (int) ND; // warn error warn error + + WUR int foo (int); + int WUR foo (int); + int fo1 WUR (int); // error error error error + int foo (int) WUR; + + #ifdef __cplusplus + } + #endif + + // gcc clang g++ clang++ + + ND extern CC int foo (int); // error error + extern CC ND int foo (int); // error error + extern CC int ND foo (int); // warn error warn error + extern CC int foo ND (int); + extern CC int foo (int) ND; // warn error warn error + + WUR extern CC int foo (int); // warn + extern CC WUR int foo (int); + extern CC int WUR foo (int); + extern CC int foo WUR (int); // error error error error + extern CC int foo (int) WUR; + + ND EXTERN_C_FUNC int foo (int); // error error + EXTERN_C_FUNC ND int foo (int); + EXTERN_C_FUNC int ND foo (int); // warn error warn error + EXTERN_C_FUNC int foo ND (int); + EXTERN_C_FUNC int foo (int) ND; // warn error warn error + + WUR EXTERN_C_FUNC int foo (int); // warn + EXTERN_C_FUNC WUR int foo (int); + EXTERN_C_FUNC int WUR foo (int); + EXTERN_C_FUNC int fo2 WUR (int); // error error error error + EXTERN_C_FUNC int foo (int) WUR; + ====================================================================== + So, if we insist on using the 'extern' keyword ('extern CC' idiom): + * If _GL_ATTRIBUTE_* expands to bracket syntax [[...]] + in both C and C++, there is one available position: + - between the function name and the parameter list. + * If _GL_ATTRIBUTE_* expands to __attribute__((...)) syntax + in both C and C++, there are several available positions: + - before the return type, + - between return type and function name, + - at the end of the declaration. + * If _GL_ATTRIBUTE_* expands to bracket syntax [[...]] in C and to + __attribute__((...)) syntax in C++, there is no available position: + it would need to come before 'extern' in C but after 'extern "C"' + in C++. + * If _GL_ATTRIBUTE_* expands to __attribute__((...)) syntax in C and + to bracket syntax [[...]] in C++, there is one available position: + - before the return type. + Whereas, if we use the 'EXTERN_C_FUNC' idiom, which conditionally + omits the 'extern' keyword: + * If _GL_ATTRIBUTE_* expands to bracket syntax [[...]] + in both C and C++, there are two available positions: + - before the return type, + - between the function name and the parameter list. + * If _GL_ATTRIBUTE_* expands to __attribute__((...)) syntax + in both C and C++, there are several available positions: + - before the return type, + - between return type and function name, + - at the end of the declaration. + * If _GL_ATTRIBUTE_* expands to bracket syntax [[...]] in C and to + __attribute__((...)) syntax in C++, there is one available position: + - before the return type. + * If _GL_ATTRIBUTE_* expands to __attribute__((...)) syntax in C and + to bracket syntax [[...]] in C++, there is one available position: + - before the return type. + The best choice is therefore to use the 'EXTERN_C_FUNC' idiom and + put the attributes before the return type. This works regardless + to what the _GL_ATTRIBUTE_* macros expand. + */ + +/* Attributes in bracket syntax [[...]] vs. attributes in __attribute__((...)) + syntax, in static/inline function definitions. + + There are similar constraints as for function declarations. However, here, + we cannot omit the storage-class specifier. Therefore, the following rule + applies: + * The macros + _GL_ATTRIBUTE_CONST + _GL_ATTRIBUTE_DEPRECATED + _GL_ATTRIBUTE_MAYBE_UNUSED + _GL_ATTRIBUTE_NODISCARD + _GL_ATTRIBUTE_PURE + _GL_ATTRIBUTE_REPRODUCIBLE + _GL_ATTRIBUTE_UNSEQUENCED + which may expand to bracket syntax [[...]], must come first, before the + storage-class specifier. + * Other _GL_ATTRIBUTE_* macros, that expand to __attribute__((...)) syntax, + are better placed between the storage-class specifier and the return + type. + */ + +/* Attributes in bracket syntax [[...]] vs. attributes in __attribute__((...)) + syntax, in variable declarations. + + At which position can they be placed? + (Last tested with gcc/g++ 14 and clang/clang++ 18.) + + =========================== foo.c = foo.cc =========================== + #ifdef __cplusplus + # define CC "C" + #else + # define CC + #endif + + #define BD [[__deprecated__]] + #define AD __attribute__ ((__deprecated__)) + + // gcc clang g++ clang++ + + BD extern CC int var; // error error + extern CC BD int var; // error error + extern CC int BD var; // warn error warn error + extern CC int var BD; + + AD extern CC int var; // warn + extern CC AD int var; + extern CC int AD var; + extern CC int var AD; + + BD extern CC int z[]; // error error + extern CC BD int z[]; // error error + extern CC int BD z[]; // warn error warn error + extern CC int z1 BD []; + extern CC int z[] BD; // warn error error + + AD extern CC int z[]; // warn + extern CC AD int z[]; + extern CC int AD z[]; + extern CC int z2 AD []; // error error error error + extern CC int z[] AD; + ====================================================================== + + * For non-array variables, the only good position is after the variable name, + that is, at the end of the declaration. + * For array variables, you will need to distinguish C and C++: + - In C, before the 'extern' keyword. + - In C++, between the 'extern "C"' and the variable's type. + */ ]dnl There is no _GL_ATTRIBUTE_ALIGNED; use stdalign's alignas instead. [ /* _GL_ATTRIBUTE_ALLOC_SIZE ((N)) declares that the Nth argument of the function @@ -151,7 +364,7 @@ AC_DEFUN([gl_COMMON_BODY], [ _GL_ATTRIBUTE_ALLOC_SIZE ((M, N)) declares that the Mth argument multiplied by the Nth argument of the function is the size of the returned memory block. */ -/* Applies to: function, pointer to function, function types. */ +/* Applies to: functions, pointer to functions, function types. */ #ifndef _GL_ATTRIBUTE_ALLOC_SIZE # if _GL_HAS_ATTRIBUTE (alloc_size) # define _GL_ATTRIBUTE_ALLOC_SIZE(args) __attribute__ ((__alloc_size__ args)) @@ -162,7 +375,7 @@ AC_DEFUN([gl_COMMON_BODY], [ /* _GL_ATTRIBUTE_ALWAYS_INLINE tells that the compiler should always inline the function and report an error if it cannot do so. */ -/* Applies to: function. */ +/* Applies to: functions. */ #ifndef _GL_ATTRIBUTE_ALWAYS_INLINE # if _GL_HAS_ATTRIBUTE (always_inline) # define _GL_ATTRIBUTE_ALWAYS_INLINE __attribute__ ((__always_inline__)) @@ -174,7 +387,7 @@ AC_DEFUN([gl_COMMON_BODY], [ /* _GL_ATTRIBUTE_ARTIFICIAL declares that the function is not important to show in stack traces when debugging. The compiler should omit the function from stack traces. */ -/* Applies to: function. */ +/* Applies to: functions. */ #ifndef _GL_ATTRIBUTE_ARTIFICIAL # if _GL_HAS_ATTRIBUTE (artificial) # define _GL_ATTRIBUTE_ARTIFICIAL __attribute__ ((__artificial__)) @@ -200,18 +413,23 @@ AC_DEFUN([gl_COMMON_BODY], [ # endif #endif -/* _GL_ATTRIBUTE_CONST declares that it is OK for a compiler to omit duplicate - calls to the function with the same arguments. - This attribute is safe for a function that neither depends on nor affects - observable state, and always returns exactly once - e.g., does not loop - forever, and does not call longjmp. - (This attribute is stricter than _GL_ATTRIBUTE_PURE.) */ +/* _GL_ATTRIBUTE_CONST declares: + It is OK for a compiler to move calls to the function and to omit + calls to the function if another call has the same arguments or the + result is not used. + This attribute is safe for a function that neither depends on + nor affects state, and always returns exactly once - + e.g., does not raise an exception, call longjmp, or loop forever. + (This attribute is stricter than _GL_ATTRIBUTE_PURE because the + function cannot observe state. It is stricter than + _GL_ATTRIBUTE_UNSEQUENCED because the function must return exactly + once and cannot depend on state addressed by its arguments.) */ /* Applies to: functions. */ #ifndef _GL_ATTRIBUTE_CONST # if _GL_HAS_ATTRIBUTE (const) # define _GL_ATTRIBUTE_CONST __attribute__ ((__const__)) # else -# define _GL_ATTRIBUTE_CONST +# define _GL_ATTRIBUTE_CONST _GL_ATTRIBUTE_UNSEQUENCED # endif #endif @@ -233,7 +451,7 @@ AC_DEFUN([gl_COMMON_BODY], [ yet. */ #ifndef _GL_ATTRIBUTE_DEALLOC_FREE # if defined __cplusplus && defined __GNUC__ && !defined __clang__ -/* Work around GCC bug <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108231> */ +/* Work around GCC bug <https://gcc.gnu.org/PR108231> */ # define _GL_ATTRIBUTE_DEALLOC_FREE \ _GL_ATTRIBUTE_DEALLOC ((void (*) (void *)) free, 1) # else @@ -459,6 +677,17 @@ AC_DEFUN([gl_COMMON_BODY], [ # endif #endif +/* _GL_ATTRIBUTE_NONNULL_IF_NONZERO (NP, NI) declares that the argument NP + (a pointer) must not be NULL if the argument NI (an integer) is != 0. */ +/* Applies to: functions. */ +#ifndef _GL_ATTRIBUTE_NONNULL_IF_NONZERO +# if _GL_HAS_ATTRIBUTE (nonnull_if_nonzero) +# define _GL_ATTRIBUTE_NONNULL_IF_NONZERO(np, ni) __attribute__ ((__nonnull_if_nonzero__ (np, ni))) +# else +# define _GL_ATTRIBUTE_NONNULL_IF_NONZERO(np, ni) +# endif +#endif + /* _GL_ATTRIBUTE_NONSTRING declares that the contents of a character array is not meant to be NUL-terminated. */ /* Applies to: struct/union members and variables that are arrays of element @@ -480,7 +709,7 @@ AC_DEFUN([gl_COMMON_BODY], [ other attributes. */ #ifndef _GL_ATTRIBUTE_NOTHROW # if defined __cplusplus -# if _GL_GNUC_PREREQ (2, 8) || __clang_major >= 4 +# if _GL_GNUC_PREREQ (2, 8) || __clang_major__ >= 4 # if __cplusplus >= 201103L # define _GL_ATTRIBUTE_NOTHROW noexcept (true) # else @@ -505,25 +734,60 @@ AC_DEFUN([gl_COMMON_BODY], [ /* Applies to: struct members, struct, union, in C++ also: class. */ #ifndef _GL_ATTRIBUTE_PACKED -# if _GL_HAS_ATTRIBUTE (packed) +/* Oracle Studio 12.6 miscompiles code with __attribute__ ((__packed__)) despite + __has_attribute OK. */ +# if _GL_HAS_ATTRIBUTE (packed) && !defined __SUNPRO_C # define _GL_ATTRIBUTE_PACKED __attribute__ ((__packed__)) # else # define _GL_ATTRIBUTE_PACKED # endif #endif -/* _GL_ATTRIBUTE_PURE declares that It is OK for a compiler to omit duplicate - calls to the function with the same arguments if observable state is not - changed between calls. - This attribute is safe for a function that does not affect - observable state, and always returns exactly once. - (This attribute is looser than _GL_ATTRIBUTE_CONST.) */ +/* _GL_ATTRIBUTE_PURE declares: + It is OK for a compiler to move calls to the function and to omit + calls to the function if another call has the same arguments or the + result is not used, and if observable state is the same. + This attribute is safe for a function that does not affect observable state + and always returns exactly once. + (This attribute is looser than _GL_ATTRIBUTE_CONST because the function + can depend on observable state. It is stricter than + _GL_ATTRIBUTE_REPRODUCIBLE because the function must return exactly + once and cannot affect state addressed by its arguments.) */ /* Applies to: functions. */ #ifndef _GL_ATTRIBUTE_PURE # if _GL_HAS_ATTRIBUTE (pure) # define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__)) # else -# define _GL_ATTRIBUTE_PURE +# define _GL_ATTRIBUTE_PURE _GL_ATTRIBUTE_REPRODUCIBLE +# endif +#endif + +/* _GL_ATTRIBUTE_REPRODUCIBLE declares: + It is OK for a compiler to move calls to the function and to omit duplicate + calls to the function with the same arguments, so long as the state + addressed by its arguments is the same and is updated in time for + the rest of the program. + This attribute is safe for a function that is effectless and idempotent; see + ISO C 23 § 6.7.12.7 for a definition of these terms. + (This attribute is looser than _GL_ATTRIBUTE_UNSEQUENCED because + the function need not be stateless and idempotent. It is looser + than _GL_ATTRIBUTE_PURE because the function need not return + exactly once and can affect state addressed by its arguments.) + See also <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2956.htm> and + <https://stackoverflow.com/questions/76847905/>. + ATTENTION! Efforts are underway to change the meaning of this attribute. + See <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3424.htm>. */ +/* Applies to: functions, pointer to functions, function types. */ +#ifndef _GL_ATTRIBUTE_REPRODUCIBLE +/* This may be revisited when gcc and clang support [[reproducible]] or possibly + __attribute__ ((__reproducible__)). */ +# ifndef _GL_BRACKET_BEFORE_ATTRIBUTE +# if _GL_HAS_ATTRIBUTE (reproducible) +# define _GL_ATTRIBUTE_REPRODUCIBLE [[reproducible]] +# endif +# endif +# ifndef _GL_ATTRIBUTE_REPRODUCIBLE +# define _GL_ATTRIBUTE_REPRODUCIBLE # endif #endif @@ -551,6 +815,35 @@ AC_DEFUN([gl_COMMON_BODY], [ # endif #endif +/* _GL_ATTRIBUTE_UNSEQUENCED declares: + It is OK for a compiler to move calls to the function and to omit duplicate + calls to the function with the same arguments, so long as the state + addressed by its arguments is the same. + This attribute is safe for a function that is effectless, idempotent, + stateless, and independent; see ISO C 23 § 6.7.12.7 for a definition of + these terms. + (This attribute is stricter than _GL_ATTRIBUTE_REPRODUCIBLE because + the function must be stateless and independent. It is looser than + _GL_ATTRIBUTE_CONST because the function need not return exactly + once and can depend on state addressed by its arguments.) + See also <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2956.htm> and + <https://stackoverflow.com/questions/76847905/>. + ATTENTION! Efforts are underway to change the meaning of this attribute. + See <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3424.htm>. */ +/* Applies to: functions, pointer to functions, function types. */ +#ifndef _GL_ATTRIBUTE_UNSEQUENCED +/* This may be revisited when gcc and clang support [[unsequenced]] or possibly + __attribute__ ((__unsequenced__)). */ +# ifndef _GL_BRACKET_BEFORE_ATTRIBUTE +# if _GL_HAS_ATTRIBUTE (unsequenced) +# define _GL_ATTRIBUTE_UNSEQUENCED [[unsequenced]] +# endif +# endif +# ifndef _GL_ATTRIBUTE_UNSEQUENCED +# define _GL_ATTRIBUTE_UNSEQUENCED +# endif +#endif + /* A helper macro. Don't use it directly. */ #ifndef _GL_ATTRIBUTE_UNUSED # if _GL_HAS_ATTRIBUTE (unused) @@ -575,6 +868,35 @@ AC_DEFUN([gl_COMMON_BODY], [ # define _GL_UNUSED_LABEL # endif #endif + +/* The following attributes enable detection of multithread-safety problems + and resource leaks at compile-time, by clang ≥ 15, when the warning option + -Wthread-safety is enabled. For usage, see + <https://clang.llvm.org/docs/ThreadSafetyAnalysis.html>. */ +#ifndef _GL_ATTRIBUTE_CAPABILITY_TYPE +# if __clang_major__ >= 15 +# define _GL_ATTRIBUTE_CAPABILITY_TYPE(concept) \ + __attribute__ ((__capability__ (concept))) +# else +# define _GL_ATTRIBUTE_CAPABILITY_TYPE(concept) +# endif +#endif +#ifndef _GL_ATTRIBUTE_ACQUIRE_CAPABILITY +# if __clang_major__ >= 15 +# define _GL_ATTRIBUTE_ACQUIRE_CAPABILITY(resource) \ + __attribute__ ((__acquire_capability__ (resource))) +# else +# define _GL_ATTRIBUTE_ACQUIRE_CAPABILITY(resource) +# endif +#endif +#ifndef _GL_ATTRIBUTE_RELEASE_CAPABILITY +# if __clang_major__ >= 15 +# define _GL_ATTRIBUTE_RELEASE_CAPABILITY(resource) \ + __attribute__ ((__release_capability__ (resource))) +# else +# define _GL_ATTRIBUTE_RELEASE_CAPABILITY(resource) +# endif +#endif ]) AH_VERBATIM([c_linkage], [/* In C++, there is the concept of "language linkage", that encompasses @@ -625,8 +947,8 @@ AC_DEFUN([gl_COMMON_BODY], [ -1 if n1 < n2 The naïve code (n1 > n2 ? 1 : n1 < n2 ? -1 : 0) produces a conditional jump with nearly all GCC versions up to GCC 10. - This variant (n1 < n2 ? -1 : n1 > n2) produces a conditional with many - GCC versions up to GCC 9. + This variant (n1 < n2 ? -1 : n1 > n2) produces a conditional jump with + many GCC versions up to GCC 9. The better code (n1 > n2) - (n1 < n2) from Hacker's Delight § 2-9 avoids conditional jumps in all GCC versions >= 3.4. */ #define _GL_CMP(n1, n2) (((n1) > (n2)) - ((n1) < (n2))) @@ -1003,7 +1325,7 @@ AC_DEFUN([gl_CC_ALLOW_WARNINGS], AC_REQUIRE([AC_PROG_CC]) AC_CACHE_CHECK([for C compiler option to allow warnings], [gl_cv_cc_wallow], - [rm -f conftest* + [rm -fr conftest* echo 'int dummy;' > conftest.c AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -c conftest.c 2>conftest1.err]) >/dev/null AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -Wno-error -c conftest.c 2>conftest2.err]) >/dev/null @@ -1016,7 +1338,7 @@ AC_DEFUN([gl_CC_ALLOW_WARNINGS], else gl_cv_cc_wallow=none fi - rm -f conftest* + rm -fr conftest* ]) case "$gl_cv_cc_wallow" in none) GL_CFLAG_ALLOW_WARNINGS='' ;; @@ -1034,7 +1356,7 @@ AC_DEFUN([gl_CXX_ALLOW_WARNINGS], if test -n "$CXX" && test "$CXX" != no; then AC_CACHE_CHECK([for C++ compiler option to allow warnings], [gl_cv_cxx_wallow], - [rm -f conftest* + [rm -fr conftest* echo 'int dummy;' > conftest.cc AC_TRY_COMMAND([${CXX-c++} $CXXFLAGS $CPPFLAGS -c conftest.cc 2>conftest1.err]) >/dev/null AC_TRY_COMMAND([${CXX-c++} $CXXFLAGS $CPPFLAGS -Wno-error -c conftest.cc 2>conftest2.err]) >/dev/null @@ -1047,7 +1369,7 @@ AC_DEFUN([gl_CXX_ALLOW_WARNINGS], else gl_cv_cxx_wallow=none fi - rm -f conftest* + rm -fr conftest* ]) case "$gl_cv_cxx_wallow" in none) GL_CXXFLAG_ALLOW_WARNINGS='' ;; @@ -1084,11 +1406,12 @@ AC_DEFUN([gl_CC_GNULIB_WARNINGS], dnl -Wno-type-limits >= 4.3 >= 3.9 dnl -Wno-undef >= 3 >= 3.9 dnl -Wno-unsuffixed-float-constants >= 4.5 + dnl -Wno-unused-const-variable >= 4.4 >= 3.9 dnl -Wno-unused-function >= 3 >= 3.9 dnl -Wno-unused-parameter >= 3 >= 3.9 dnl cat > conftest.c <<\EOF - #if __GNUC__ >= 3 || (__clang_major__ + (__clang_minor__ >= 9) > 3) + #if (__GNUC__ >= 3 && !defined __clang__) || (__clang_major__ + (__clang_minor__ >= 9) > 3) -Wno-cast-qual -Wno-conversion -Wno-float-equal @@ -1097,23 +1420,26 @@ AC_DEFUN([gl_CC_GNULIB_WARNINGS], -Wno-unused-function -Wno-unused-parameter #endif - #if __GNUC__ + (__GNUC_MINOR__ >= 9) > 4 || (__clang_major__ + (__clang_minor__ >= 9) > 3) + #if (__GNUC__ + (__GNUC_MINOR__ >= 9) > 4 && !defined __clang__) || (__clang_major__ + (__clang_minor__ >= 9) > 3) -Wno-float-conversion #endif - #if __GNUC__ >= 7 || (__clang_major__ + (__clang_minor__ >= 9) > 3) + #if (__GNUC__ >= 7 && !defined __clang__) || (__clang_major__ + (__clang_minor__ >= 9) > 3) -Wimplicit-fallthrough #endif - #if __GNUC__ + (__GNUC_MINOR__ >= 8) > 4 || (__clang_major__ + (__clang_minor__ >= 9) > 3) + #if (__GNUC__ + (__GNUC_MINOR__ >= 8) > 4 && !defined __clang__) || (__clang_major__ + (__clang_minor__ >= 9) > 3) -Wno-pedantic #endif #if 3 < __clang_major__ + (9 <= __clang_minor__) -Wno-tautological-constant-out-of-range-compare #endif - #if __GNUC__ + (__GNUC_MINOR__ >= 3) > 4 || (__clang_major__ + (__clang_minor__ >= 9) > 3) + #if (__GNUC__ + (__GNUC_MINOR__ >= 3) > 4 && !defined __clang__) || (__clang_major__ + (__clang_minor__ >= 9) > 3) -Wno-sign-conversion -Wno-type-limits #endif - #if __GNUC__ + (__GNUC_MINOR__ >= 5) > 4 + #if (__GNUC__ + (__GNUC_MINOR__ >= 4) > 4 && !defined __clang__) || (__clang_major__ + (__clang_minor__ >= 9) > 3) + -Wno-unused-const-variable + #endif + #if (__GNUC__ + (__GNUC_MINOR__ >= 5) > 4 && !defined __clang__) -Wno-unsuffixed-float-constants #endif EOF @@ -1237,13 +1563,25 @@ AC_DEFUN([gl_CHECK_FUNCS_CASE_FOR_MACOS], if test $[ac_cv_func_][$1] = yes; then [gl_cv_onwards_func_][$1]=yes else + dnl This is a bit complicated, because here we need the behaviour + dnl of AC_CHECK_DECL before the + dnl commit e1bbc9b93cdff61d70719c224b37970e065008bb (2025-05-26). + [ac_cv_have_decl_][$1][_saved]="$[ac_cv_have_decl_][$1]" unset [ac_cv_have_decl_][$1] + ac_c_future_darwin_options_saved="$ac_c_future_darwin_options" + ac_cxx_future_darwin_options_saved="$ac_cxx_future_darwin_options" + ac_c_future_darwin_options= + ac_cxx_future_darwin_options= AC_CHECK_DECL([$1], , , [$2]) + ac_c_future_darwin_options="$ac_c_future_darwin_options_saved" + ac_cxx_future_darwin_options="$ac_cxx_future_darwin_options_saved" if test $[ac_cv_have_decl_][$1] = yes; then [gl_cv_onwards_func_][$1]='future OS version' else [gl_cv_onwards_func_][$1]=no fi + [ac_cv_have_decl_][$1]="$[ac_cv_have_decl_][$1][_saved]" + unset [ac_cv_have_decl_][$1][_saved] fi else AC_CHECK_FUNC([$1]) @@ -1296,7 +1634,7 @@ dnl dnl This macro sets two variables: dnl - gl_cv_onwards_func_<func> to yes / no / "future OS version" dnl - ac_cv_func_<func> to yes / no / no -dnl The first variable allows to distinguish all three cases. +dnl The first variable allows distinguishing all three cases. dnl The second variable is set, so that an invocation dnl gl_CHECK_FUNCS_ANDROID([func], [[#include <foo.h>]]) dnl can be used as a drop-in replacement for @@ -1349,7 +1687,7 @@ dnl dnl This macro sets two variables: dnl - gl_cv_onwards_func_<func> to yes / no / "future OS version" dnl - ac_cv_func_<func> to yes / no / no -dnl The first variable allows to distinguish all three cases. +dnl The first variable allows distinguishing all three cases. dnl The second variable is set, so that an invocation dnl gl_CHECK_FUNCS_MACOS([func], [[#include <foo.h>]]) dnl can be used as a drop-in replacement for |