When using C++11, use static_assert to implement COMPILE_ASSERT.
Tag COMPILE_ASSERT with ALLOW_UNUSED for non-C++11 GCC 4.8, which otherwise
produces warnings under -Wunused-local-typedefs. That warning is currently
disabled in Chromium (r194779), but the ultimate goal should be to enable that
warning.
BUG=321833
R=thakis@chromium.org
Review URL: https://codereview.chromium.org/77343005
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236356 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/base/basictypes.h b/base/basictypes.h
index 10275f9..e77d7b1 100644
--- a/base/basictypes.h
+++ b/base/basictypes.h
@@ -9,6 +9,7 @@
#include <stddef.h> // For size_t
#include <string.h> // for memcpy
+#include "base/compiler_specific.h"
#include "base/port.h" // Types that only need exist on certain systems
#ifndef COMPILER_MSVC
@@ -215,13 +216,21 @@
// the expression is false, most compilers will issue a warning/error
// containing the name of the variable.
+#undef COMPILE_ASSERT
+
+#if __cplusplus >= 201103L
+
+// Under C++11, just use static_assert.
+#define COMPILE_ASSERT(expr, msg) static_assert(expr, #msg)
+
+#else
+
template <bool>
struct CompileAssert {
};
-#undef COMPILE_ASSERT
#define COMPILE_ASSERT(expr, msg) \
- typedef CompileAssert<(bool(expr))> msg[bool(expr) ? 1 : -1]
+ typedef CompileAssert<(bool(expr))> msg[bool(expr) ? 1 : -1] ALLOW_UNUSED
// Implementation details of COMPILE_ASSERT:
//
@@ -264,6 +273,7 @@
// This is to avoid running into a bug in MS VC 7.1, which
// causes ((0.0) ? 1 : -1) to incorrectly evaluate to 1.
+#endif
// bit_cast<Dest,Source> is a template function that implements the
// equivalent of "*reinterpret_cast<Dest*>(&source)". We need this in
