diff options
Diffstat (limited to 'gnulib-m4/gnulib-common.m4')
| -rw-r--r-- | gnulib-m4/gnulib-common.m4 | 113 |
1 files changed, 68 insertions, 45 deletions
diff --git a/gnulib-m4/gnulib-common.m4 b/gnulib-m4/gnulib-common.m4 index 134bfba2..26eef771 100644 --- a/gnulib-m4/gnulib-common.m4 +++ b/gnulib-m4/gnulib-common.m4 @@ -1,6 +1,6 @@ # gnulib-common.m4 -# serial 113 -dnl Copyright (C) 2007-2025 Free Software Foundation, Inc. +# serial 115 +dnl Copyright (C) 2007-2026 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. @@ -414,22 +414,25 @@ AC_DEFUN([gl_COMMON_BODY], [ #endif /* _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 - + It is OK for a compiler to move a call, or omit a duplicate call + and reuse a cached return value, even if the state changes between calls. + It is also OK to omit a call if the result is not used. + This attribute is safe if the function does not change observable state, + returns a value determined solely by its arguments' values + without examining 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.) */ + function cannot observe state. Unlike _GL_ATTRIBUTE_UNSEQUENCED + the function must return exactly once and cannot access state + addressed by its pointer arguments or that happens to have the same + value for all calls to the function, but the function is allowed to + return a pointer to storage that can be modified later. */ /* Applies to: functions. */ #ifndef _GL_ATTRIBUTE_CONST # if _GL_HAS_ATTRIBUTE (const) # define _GL_ATTRIBUTE_CONST __attribute__ ((__const__)) # else -# define _GL_ATTRIBUTE_CONST _GL_ATTRIBUTE_UNSEQUENCED +# define _GL_ATTRIBUTE_CONST # endif #endif @@ -590,7 +593,9 @@ AC_DEFUN([gl_COMMON_BODY], [ /* _GL_ATTRIBUTE_MAYBE_UNUSED declares that it is not a programming mistake if the entity is not used. The compiler should not warn if the entity is not - used. */ + used. However, 'int _GL_UNNAMED (i)' is preferable to + '_GL_ATTRIBUTE_MAYBE_UNUSED int i' when parameter I is unused + regardless of preprocessor macro settings. */ /* Applies to: - function, variable, - struct, union, struct/union member, @@ -744,39 +749,40 @@ AC_DEFUN([gl_COMMON_BODY], [ #endif /* _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. + It is OK for a compiler to move a call, or omit a duplicate call + and reuse a cached return value, if observable state is the same. + It is also OK to omit a call if the return value is not used. + This attribute is safe if the function does not change observable state, + returns a value determined solely by its arguments's values + together with 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.) */ + can depend on observable state. + Unlike _GL_ATTRIBUTE_REPRODUCIBLE the function must return exactly + once and cannot change state addressed by its arguments, but the + function can return a pointer to storage whose contents change later.) */ /* Applies to: functions. */ #ifndef _GL_ATTRIBUTE_PURE # if _GL_HAS_ATTRIBUTE (pure) # define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__)) # else -# define _GL_ATTRIBUTE_PURE _GL_ATTRIBUTE_REPRODUCIBLE +# define _GL_ATTRIBUTE_PURE # 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. + It is OK for a compiler to move a call, or omit a duplicate call + and reuse a cached value returned either directly or indirectly via + a pointer, if other observable state is the same; + however, pointer arguments cannot alias. + This attribute is safe for a function that is effectless and idempotent; + see ISO C 23 § 6.7.13.8 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.) + the function need not be stateless or independent. + Unlike _GL_ATTRIBUTE_PURE the function need not return exactly once + and can change state addressed by its pointer arguments, but the + function cannot return a pointer to storage whose contents change later.) 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>. */ + <https://stackoverflow.com/questions/76847905/>. */ /* Applies to: functions, pointer to functions, function types. */ #ifndef _GL_ATTRIBUTE_REPRODUCIBLE /* This may be revisited when gcc and clang support [[reproducible]] or possibly @@ -816,20 +822,22 @@ AC_DEFUN([gl_COMMON_BODY], [ #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. + It is OK for a compiler to move a call, or omit a duplicate call + and reuse a cached value returned either directly or indirectly via + a pointer, if the state addressed by its pointer arguments is the same; + however, pointer arguments cannot alias. 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 + stateless, and independent; see ISO C 23 § 6.7.13.8 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.) + the function must be stateless and independent. Unlike + _GL_ATTRIBUTE_CONST the function need not return exactly once, and + can depend on state accessed via its pointer arguments or that + happens to have the same value for all calls to the function, but + the function cannot return a pointer to storage whose contents + change later.) 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>. */ + <https://stackoverflow.com/questions/76847905/>. */ /* Applies to: functions, pointer to functions, function types. */ #ifndef _GL_ATTRIBUTE_UNSEQUENCED /* This may be revisited when gcc and clang support [[unsequenced]] or possibly @@ -869,6 +877,21 @@ AC_DEFUN([gl_COMMON_BODY], [ # endif #endif +/* _GL_UNNAMED (ID) is the "name" of an unnamed function parameter. + Each of the function's unnamed parameters should have a unique "name". + The "name" cannot be used. This ports both to C17 and earlier, which + lack unnamed parameters, and to C++ and later C, which have them. */ +/* Applies to: + - function parameters. */ +#ifndef _GL_UNNAMED +# if ((defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) < 202311 \ + && !defined __cplusplus) +# define _GL_UNNAMED(id) unnamed_##id _GL_ATTRIBUTE_UNUSED +# else +# define _GL_UNNAMED(id) +# 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 @@ -1406,7 +1429,7 @@ 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-const-variable >= 6.1 >= 3.9 dnl -Wno-unused-function >= 3 >= 3.9 dnl -Wno-unused-parameter >= 3 >= 3.9 dnl @@ -1436,7 +1459,7 @@ AC_DEFUN([gl_CC_GNULIB_WARNINGS], -Wno-sign-conversion -Wno-type-limits #endif - #if (__GNUC__ + (__GNUC_MINOR__ >= 4) > 4 && !defined __clang__) || (__clang_major__ + (__clang_minor__ >= 9) > 3) + #if (__GNUC__ + (__GNUC_MINOR__ >= 1) > 6 && !defined __clang__) || (__clang_major__ + (__clang_minor__ >= 9) > 3) -Wno-unused-const-variable #endif #if (__GNUC__ + (__GNUC_MINOR__ >= 5) > 4 && !defined __clang__) |