Yesterday I did: > 2024-07-29 Bruno Haible <br...@clisp.org> > > Avoid g++ "warning: attributes are not permitted in this position". > * m4/gnulib-common.m4 (gl_COMMON_BODY): Add more comments. Define > _GL_BRACKET_USABLE. ...
But I'm not happy with it, as it disables the use of the [[...]] attributes
entirely.
A better way of handling this matter is
- by distinguishing function declarations from other declarations,
- by omitting the 'extern' keyword from specific function declarations
(since 'extern' is optional, per ISO C 23 § 6.2.2.(5)).
Here are two patches:
- 0001 reverts that part of yesterday's change and places the attributes
in a position where both C and C++ accept them.
- 0002 documents the placements of attribute markers better.
2024-07-30 Bruno Haible <br...@clisp.org>
attribute: Improve documentation.
* lib/attribute.h: Clarify where to place the various attributes.
2024-07-30 Bruno Haible <br...@clisp.org>
Reenable use of attributes in bracket syntax [[...]] (regr. yesterday).
* m4/gnulib-common.m4 (gl_COMMON_BODY): Add more comments. Don't define
_GL_BRACKET_USABLE.
* lib/c++defs.h (_GL_EXTERN_C_FUNC): New macro.
(_GL_FUNCDECL_RPL, _GL_FUNCDECL_RPL_1, _GL_FUNCDECL_SYS): Expect the
attributes in an optional 4th argument. Expand them before the return
type.
* lib/arpa_inet.in.h: Update all _GL_FUNCDECL_RPL and _GL_FUNCDECL_SYS
invocations.
* lib/dirent.in.h: Likewise.
* lib/error.in.h: Likewise.
* lib/fcntl.in.h: Likewise.
* lib/fnmatch.in.h: Likewise.
* lib/glob.in.h: Likewise.
* lib/iconv.in.h: Likewise.
* lib/inttypes.in.h: Likewise.
* lib/locale.in.h: Likewise.
* lib/malloc.in.h: Likewise.
* lib/math.in.h: Likewise.
* lib/monetary.in.h: Likewise.
* lib/netdb.in.h: Likewise.
* lib/pthread.in.h: Likewise.
* lib/search.in.h: Likewise.
* lib/signal.in.h: Likewise.
* lib/spawn.in.h: Likewise.
* lib/stdio.in.h: Likewise.
* lib/stdlib.in.h: Likewise.
* lib/string.in.h: Likewise.
* lib/sys_random.in.h: Likewise.
* lib/sys_resource.in.h: Likewise.
* lib/sys_socket.in.h: Likewise.
* lib/sys_stat.in.h: Likewise.
* lib/sys_time.in.h: Likewise.
* lib/threads.in.h: Likewise.
* lib/time.in.h: Likewise.
* lib/uchar.in.h: Likewise.
* lib/unistd.in.h: Likewise.
* lib/utime.in.h: Likewise.
* lib/wchar.in.h: Likewise.
* lib/wctype.in.h: Likewise.
* lib/c-vasprintf.h (c_aszprintf, c_vaszprintf, c_asprintf,
c_vasprintf): Move _GL_ATTRIBUTE_NODISCARD back to the beginning of the
declaration.
0001-Reenable-use-of-attributes-in-bracket-syntax-.-regr..patch.gz
Description: application/gzip
From a05ec21958eb6afb6c7e419b8fb543e26c0d00e1 Mon Sep 17 00:00:00 2001
From: Bruno Haible <br...@clisp.org>
Date: Tue, 30 Jul 2024 22:01:27 +0200
Subject: [PATCH 2/2] attribute: Improve documentation.
* lib/attribute.h: Clarify where to place the various attributes.
---
ChangeLog | 5 +++++
lib/attribute.h | 49 +++++++++++++++++++++++++++++++++++++++++++------
2 files changed, 48 insertions(+), 6 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 6bf78d04ff..872cc0f6cb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2024-07-30 Bruno Haible <br...@clisp.org>
+
+ attribute: Improve documentation.
+ * lib/attribute.h: Clarify where to place the various attributes.
+
2024-07-30 Bruno Haible <br...@clisp.org>
Reenable use of attributes in bracket syntax [[...]] (regr. yesterday).
diff --git a/lib/attribute.h b/lib/attribute.h
index 604965a6d1..186faa5526 100644
--- a/lib/attribute.h
+++ b/lib/attribute.h
@@ -20,12 +20,49 @@
/* Provide public ATTRIBUTE_* names for the private _GL_ATTRIBUTE_*
macros used within Gnulib. */
-/* These attributes can be placed in two ways:
- - At the start of a declaration (i.e. even before storage-class
- specifiers!); then they apply to all entities that are declared
- by the declaration.
- - Immediately after the name of an entity being declared by the
- declaration; then they apply to that entity only. */
+/* The placement of these attributes depends on the kind of declaration
+ and, in some cases, also on the programming language (C vs. C++).
+
+ In function declarations and function definitions:
+
+ * ATTRIBUTE_NOTHROW must come after the parameter list.
+
+ * The macros
+ ATTRIBUTE_CONST
+ ATTRIBUTE_PURE
+ DEPRECATED
+ MAYBE_UNUSED
+ NODISCARD
+ REPRODUCIBLE
+ UNSEQUENCED
+ must come before the return type, and more precisely:
+ - In a function declaration/definition without a storage-class
+ specifier: at the beginning of the declaration/definition.
+ - In a function declaration/definition with a storage-class
+ specifier:
+ - In C: before the storage-class specifier.
+ - In C++: between the storage-class specifier and the return type.
+
+ * The other macros can be placed
+ - Either
+ - In a function declaration/definition without a storage-class
+ specifier: at the beginning of the declaration/definition.
+ - In a function declaration/definition with a storage-class
+ specifier: between the storage-class specifier and the return
+ type.
+ - Or after the parameter list,
+ ∙ but after ATTRIBUTE_NOTHROW if present.
+
+ In other declarations, such as variable declarations:
+
+ * Either
+ - In C: before the storage-class specifier.
+ - In C++: between the storage-class specifier and the return type.
+ Then they apply to all entities that are declared by the declaration.
+
+ * Or immediately after the name of an entity being declared by the
+ declaration. Then they apply to that entity only.
+ */
#ifndef _GL_ATTRIBUTE_H
#define _GL_ATTRIBUTE_H
--
2.34.1
