clang has _Static_assert and, in C++ mode, also 'static_assert' (at least in
clang >= 4). Gnulib can make use of it.
2020-08-16 Bruno Haible <br...@clisp.org>
Use _Static_assert and static_assert primitives when present on clang.
* lib/cdefs.h (_Static_assert): Don't define as a macro on clang.
* lib/verify.h (_GL_HAVE__STATIC_ASSERT, _GL_HAVE__STATIC_ASSERT1,
_GL_HAVE_STATIC_ASSERT1): Define as appropriate on clang.
diff --git a/lib/cdefs.h b/lib/cdefs.h
index b7f60c1..67ad180 100644
--- a/lib/cdefs.h
+++ b/lib/cdefs.h
@@ -465,7 +465,8 @@
#if (!defined _Static_assert && !defined __cplusplus \
&& (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) < 201112 \
- && (!__GNUC_PREREQ (4, 6) || defined __STRICT_ANSI__))
+ && (!(__GNUC_PREREQ (4, 6) || __clang_major__ >= 4) \
+ || defined __STRICT_ANSI__))
# define _Static_assert(expr, diagnostic) \
extern int (*__Static_assert_function (void)) \
[!!sizeof (struct { int __error_if_negative: (expr) ? 2 : -1; })]
diff --git a/lib/verify.h b/lib/verify.h
index 58172f3..0ba8d57 100644
--- a/lib/verify.h
+++ b/lib/verify.h
@@ -23,11 +23,15 @@
/* Define _GL_HAVE__STATIC_ASSERT to 1 if _Static_assert (R, DIAGNOSTIC)
works as per C11. This is supported by GCC 4.6.0 and later, in C
- mode.
+ mode, and by clang (also in C++ mode).
Define _GL_HAVE__STATIC_ASSERT1 to 1 if _Static_assert (R) works as
- per C2X, and define _GL_HAVE_STATIC_ASSERT1 if static_assert (R)
- works as per C++17. This is supported by GCC 9.1 and later.
+ per C2X. This is supported by GCC 9.1 and later, and by clang in
+ C++1z mode.
+
+ Define _GL_HAVE_STATIC_ASSERT1 if static_assert (R) works as per
+ C++17. This is supported by GCC 9.1 and later, and by clang in
+ C++1z mode.
Support compilers claiming conformance to the relevant standard,
and also support GCC when not pedantic. If we were willing to slow
@@ -35,7 +39,8 @@
since this affects only the quality of diagnostics, why bother? */
#ifndef __cplusplus
# if (201112L <= __STDC_VERSION__ \
- || (!defined __STRICT_ANSI__ && 4 < __GNUC__ + (6 <= __GNUC_MINOR__)))
+ || (!defined __STRICT_ANSI__ \
+ && (4 < __GNUC__ + (6 <= __GNUC_MINOR__) || 4 <= __clang_major__)))
# define _GL_HAVE__STATIC_ASSERT 1
# endif
# if (202000L <= __STDC_VERSION__ \
@@ -43,7 +48,15 @@
# define _GL_HAVE__STATIC_ASSERT1 1
# endif
#else
-# if 201703L <= __cplusplus || 9 <= __GNUC__
+# if 4 <= __clang_major__
+# define _GL_HAVE__STATIC_ASSERT 1
+# endif
+# if 4 <= __clang_major__ && 201411 <= __cpp_static_assert
+# define _GL_HAVE__STATIC_ASSERT1 1
+# endif
+# if 201703L <= __cplusplus \
+ || 9 <= __GNUC__ \
+ || (4 <= __clang_major__ && 201411 <= __cpp_static_assert)
# define _GL_HAVE_STATIC_ASSERT1 1
# endif
#endif
