On 9/14/22 04:35, Bruno Haible wrote:
-# define _Static_assert(...) \ - _GL_VERIFY (__VA_ARGS__, "static assertion failed", -) +# define _Static_assert(R, ...) \ + _GL_VERIFY ((R), "static assertion failed", -)
Unfortunately this doesn't conform to strict C99, which requires the updated _Static_assert to be called with at least two arguments. I discovered this while compiling bleeding-edge gzip on AIX and on Solaris. I worked around the problem by installing the attached patch, though since I don't use MSVC I'm not sure I got the new #if exactly right.
Also, does MSVC require the "(R)" to be parenthesized? I also noticed what would ordinarily be unnecessary parentheses later on, in the MSVC-specific '# define _GL_SA1(a1) static_assert ((a1), "static assertion failed")'. Ordinarily I like to leave those parentheses out but if MSVC needs them obviously we should keep them.
From 14a7b0ce5462c90ce86d97bf952185ec2500d341 Mon Sep 17 00:00:00 2001 From: Paul Eggert <egg...@cs.ucla.edu> Date: Wed, 28 Dec 2022 14:15:43 -0800 Subject: [PATCH] assert-h: port static_assert to strict C99 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit * lib/verify.h (_GL_VERIFY): Port MSVC hack back to C99. Problem found when testing bleeding-edge gzip on IBM XL C for AIX, V12.1 (5765-J02, 5725-C72), which complained ‘"malloca.c", line 42.56: 1506-041 (E) The invocation of macro _Static_assert contains fewer arguments than are required by the macro definition.’ This diagnostic is valid because C99 requires that if you #define _Static_assert(R, ...) you must call _Static_assert with at least two arguments. I found a similar problem with Sun C 5.9 SunOS_sparc Patch 124867-12 2009/11/22. --- ChangeLog | 13 +++++++++++++ lib/verify.h | 16 +++++++++++----- 2 files changed, 24 insertions(+), 5 deletions(-) diff --git a/ChangeLog b/ChangeLog index be0fb22078..49f88777eb 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,16 @@ +2022-12-28 Paul Eggert <egg...@cs.ucla.edu> + + assert-h: port static_assert to strict C99 + * lib/verify.h (_GL_VERIFY): Port MSVC hack back to C99. + Problem found when testing bleeding-edge gzip on IBM XL C for AIX, + V12.1 (5765-J02, 5725-C72), which complained ‘"malloca.c", line + 42.56: 1506-041 (E) The invocation of macro _Static_assert + contains fewer arguments than are required by the macro + definition.’ This diagnostic is valid because C99 requires + that if you #define _Static_assert(R, ...) you must call + _Static_assert with at least two arguments. I found a similar + problem with Sun C 5.9 SunOS_sparc Patch 124867-12 2009/11/22. + 2022-12-27 Paul Eggert <egg...@cs.ucla.edu> file-has-acl: fix recently-introduced NFSv4 bug diff --git a/lib/verify.h b/lib/verify.h index 5225a8e616..cb635a9fc2 100644 --- a/lib/verify.h +++ b/lib/verify.h @@ -223,8 +223,15 @@ template <int w> /* _GL_STATIC_ASSERT_H is defined if this code is copied into assert.h. */ #ifdef _GL_STATIC_ASSERT_H # if !defined _GL_HAVE__STATIC_ASSERT1 && !defined _Static_assert -# define _Static_assert(R, ...) \ - _GL_VERIFY ((R), "static assertion failed", -) +# if !defined _MSC_VER || defined __clang__ +# define _Static_assert(...) \ + _GL_VERIFY (__VA_ARGS__, "static assertion failed", -) +# else + /* Work around MSVC preprocessor incompatibility with ISO C; see + <https://stackoverflow.com/questions/5134523/>. */ +# define _Static_assert(R, ...) \ + _GL_VERIFY ((R), "static assertion failed", -) +# endif # endif # if (!defined static_assert \ && __STDC_VERSION__ < 202311 \ @@ -235,9 +242,8 @@ template <int w> /* MSVC 14 in C++ mode supports the two-arguments static_assert but not the one-argument static_assert, and it does not support _Static_assert. We have to play preprocessor tricks to distinguish the two cases. - Since the MSVC preprocessor is not ISO C compliant (cf. - <https://stackoverflow.com/questions/5134523/>), the solution is specific - to MSVC. */ + Since the MSVC preprocessor is not ISO C compliant (see above),. + the solution is specific to MSVC. */ # define _GL_EXPAND(x) x # define _GL_SA1(a1) static_assert ((a1), "static assertion failed") # define _GL_SA2 static_assert -- 2.25.1
