On 12/11/17 17:12, Tom Lane wrote:
> Peter Eisentraut <peter.eisentr...@2ndquadrant.com> writes:
>> On 12/11/17 16:45, Tom Lane wrote:
>>> (BTW, why is it that we can't fall back on the negative-width-bitfield
>>> trick for old g++?)
>
>> The complaint is
>> error: types may not be defined in 'sizeof' expressions
>
> Hmm, well, surely there's more than one way to do that; the sizeof
> is just a convenient way to wrap it in C. Wouldn't a typedef serve
> just as well?
Here is another attempt, which has the desired effect with the handful
of compilers I have available.
(With the recent changes to AllocSetContextCreate() using a static
assertion, the current state now breaks actual extensions written in C++
in some configurations, so this has become a bit of a must-fix for PG11.)
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
From d631fcb1fb2babef618bc9b3eba3f5591970a609 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <pete...@gmx.net>
Date: Tue, 30 Aug 2016 12:00:00 -0400
Subject: [PATCH v4] Add support for static assertions in C++
This allows modules written in C++ to use or include header files that
use StaticAssertStmt() etc.
---
src/include/c.h | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/src/include/c.h b/src/include/c.h
index 11fcffbae3..22535a7deb 100644
--- a/src/include/c.h
+++ b/src/include/c.h
@@ -754,6 +754,7 @@ typedef NameData *Name;
* about a negative width for a struct bit-field. This will not include a
* helpful error message, but it beats not getting an error at all.
*/
+#ifndef __cplusplus
#ifdef HAVE__STATIC_ASSERT
#define StaticAssertStmt(condition, errmessage) \
do { _Static_assert(condition, errmessage); } while(0)
@@ -765,6 +766,19 @@ typedef NameData *Name;
#define StaticAssertExpr(condition, errmessage) \
StaticAssertStmt(condition, errmessage)
#endif /* HAVE__STATIC_ASSERT
*/
+#else /* C++ */
+#if defined(__cpp_static_assert) && __cpp_static_assert >= 200410
+#define StaticAssertStmt(condition, errmessage) \
+ static_assert(condition, errmessage)
+#define StaticAssertExpr(condition, errmessage) \
+ StaticAssertStmt(condition, errmessage)
+#else
+#define StaticAssertStmt(condition, errmessage) \
+ do { struct static_assert_struct { int static_assert_failure :
(condition) ? 1 : -1; }; } while(0)
+#define StaticAssertExpr(condition, errmessage) \
+ ({ StaticAssertStmt(condition, errmessage); })
+#endif
+#endif /* C++ */
/*
base-commit: 56a95ee5118bf6d46e261b8d352f7dafac10587d
--
2.15.1
