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Diffstat (limited to 'third_party/macros.h')
| -rw-r--r-- | third_party/macros.h | 87 |
1 files changed, 0 insertions, 87 deletions
diff --git a/third_party/macros.h b/third_party/macros.h deleted file mode 100644 index 93c44857a9..0000000000 --- a/third_party/macros.h +++ /dev/null @@ -1,87 +0,0 @@ -// Copyright 2014 The Chromium Authors. All rights reserved. -// Use of this source code is governed by a BSD-style license that can be -// found in the LICENSE file. - -// This file contains macros and macro-like constructs (e.g., templates) that -// are commonly used throughout Chromium source. (It may also contain things -// that are closely related to things that are commonly used that belong in this -// file.) - -#ifndef BASE_MACROS_H_ -#define BASE_MACROS_H_ - -// The COMPILE_ASSERT macro can be used to verify that a compile time -// expression is true. For example, you could use it to verify the -// size of a static array: -// -// COMPILE_ASSERT(ARRAYSIZE_UNSAFE(content_type_names) == CONTENT_NUM_TYPES, -// content_type_names_incorrect_size); -// -// or to make sure a struct is smaller than a certain size: -// -// COMPILE_ASSERT(sizeof(foo) < 128, foo_too_large); -// -// The second argument to the macro is the name of the variable. If -// 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 { -}; - -#define COMPILE_ASSERT(expr, msg) \ - typedef CompileAssert<(bool(expr))> msg[bool(expr) ? 1 : -1] ALLOW_UNUSED - -// Implementation details of COMPILE_ASSERT: -// -// - COMPILE_ASSERT works by defining an array type that has -1 -// elements (and thus is invalid) when the expression is false. -// -// - The simpler definition -// -// #define COMPILE_ASSERT(expr, msg) typedef char msg[(expr) ? 1 : -1] -// -// does not work, as gcc supports variable-length arrays whose sizes -// are determined at run-time (this is gcc's extension and not part -// of the C++ standard). As a result, gcc fails to reject the -// following code with the simple definition: -// -// int foo; -// COMPILE_ASSERT(foo, msg); // not supposed to compile as foo is -// // not a compile-time constant. -// -// - By using the type CompileAssert<(bool(expr))>, we ensures that -// expr is a compile-time constant. (Template arguments must be -// determined at compile-time.) -// -// - The outer parentheses in CompileAssert<(bool(expr))> are necessary -// to work around a bug in gcc 3.4.4 and 4.0.1. If we had written -// -// CompileAssert<bool(expr)> -// -// instead, these compilers will refuse to compile -// -// COMPILE_ASSERT(5 > 0, some_message); -// -// (They seem to think the ">" in "5 > 0" marks the end of the -// template argument list.) -// -// - The array size is (bool(expr) ? 1 : -1), instead of simply -// -// ((expr) ? 1 : -1). -// -// 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 - -#endif // BASE_MACROS_H_ |