From 481018f2804065cb5ed1cde75b7c0596aeef959a Mon Sep 17 00:00:00 2001
From: Peter Eisentraut
Date: Mon, 25 Mar 2019 09:35:29 +0100
Subject: Add macro to cast away volatile without allowing changes to
 underlying type

This adds unvolatize(), which works just like unconstify() but for volatile.

Discussion: https://www.postgresql.org/message-id/flat/7a5cbea7-b8df-e910-0f10-04014bcad701%402ndquadrant.com
---
 src/include/c.h | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

(limited to 'src/include/c.h')

diff --git a/src/include/c.h b/src/include/c.h
index 658be50e0d..33c9518195 100644
--- a/src/include/c.h
+++ b/src/include/c.h
@@ -1122,7 +1122,7 @@ typedef union PGAlignedXLogBlock
 #endif
 
 /*
- * Macro that allows to cast constness away from an expression, but doesn't
+ * Macro that allows to cast constness and volatile away from an expression, but doesn't
  * allow changing the underlying type.  Enforcement of the latter
  * currently only works for gcc like compilers.
  *
@@ -1141,9 +1141,15 @@ typedef union PGAlignedXLogBlock
 	(StaticAssertExpr(__builtin_types_compatible_p(__typeof(expr), const underlying_type), \
 					  "wrong cast"), \
 	 (underlying_type) (expr))
+#define unvolatize(underlying_type, expr) \
+	(StaticAssertExpr(__builtin_types_compatible_p(__typeof(expr), volatile underlying_type), \
+					  "wrong cast"), \
+	 (underlying_type) (expr))
 #else
 #define unconstify(underlying_type, expr) \
 	((underlying_type) (expr))
+#define unvolatize(underlying_type, expr) \
+	((underlying_type) (expr))
 #endif
 
 /* ----------------------------------------------------------------
-- 
cgit v1.2.3