| // 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. |
| |
| #ifndef MOJO_PUBLIC_C_SYSTEM_MACROS_H_ |
| #define MOJO_PUBLIC_C_SYSTEM_MACROS_H_ |
| |
| #include <stddef.h> |
| |
| // Annotate a variable indicating it's okay if it's unused. |
| // Use like: |
| // int x = ...; |
| // MOJO_ALLOW_UNUSED_LOCAL(x); |
| #define MOJO_ALLOW_UNUSED_LOCAL(x) false ? (void)x : (void)0 |
| |
| // Annotate a function indicating that the caller must examine the return value. |
| // Use like: |
| // int foo() MOJO_WARN_UNUSED_RESULT; |
| // Note that it can only be used on the prototype, and not the definition. |
| #if defined(__GNUC__) |
| #define MOJO_WARN_UNUSED_RESULT __attribute__((warn_unused_result)) |
| #else |
| #define MOJO_WARN_UNUSED_RESULT |
| #endif |
| |
| #ifdef __cplusplus |
| // Used to explicitly mark the return value of a function as unused. If you are |
| // really sure you don't want to do anything with the return value of a function |
| // that has been marked WARN_UNUSED_RESULT, wrap it with this. Example: |
| // |
| // scoped_ptr<MyType> my_var = ...; |
| // if (TakeOwnership(my_var.get()) == SUCCESS) |
| // mojo_ignore_result(my_var.release()); |
| // |
| template <typename T> |
| inline void mojo_ignore_result(const T&) { |
| } |
| #endif |
| |
| // Assert things at compile time. (|msg| should be a valid identifier name.) |
| // This macro is currently C++-only, but we want to use it in the C core.h. |
| // Use like: |
| // MOJO_STATIC_ASSERT(sizeof(Foo) == 12, "Foo has invalid size"); |
| #if defined(__cplusplus) |
| #define MOJO_STATIC_ASSERT(expr, msg) static_assert(expr, msg) |
| #else |
| #define MOJO_STATIC_ASSERT(expr, msg) |
| #endif |
| |
| // Like the C++11 |alignof| operator. |
| #if __cplusplus >= 201103L |
| #define MOJO_ALIGNOF(type) alignof(type) |
| #elif defined(__GNUC__) |
| #define MOJO_ALIGNOF(type) __alignof__(type) |
| #elif defined(_MSC_VER) |
| // The use of |sizeof| is to work around a bug in MSVC 2010 (see |
| // http://goo.gl/isH0C; supposedly fixed since then). |
| #define MOJO_ALIGNOF(type) (sizeof(type) - sizeof(type) + __alignof(type)) |
| #else |
| #error "Please define MOJO_ALIGNOF() for your compiler." |
| #endif |
| |
| // Specify the alignment of a |struct|, etc. |
| // Use like: |
| // struct MOJO_ALIGNAS(8) Foo { ... }; |
| // Unlike the C++11 |alignas()|, |alignment| must be an integer. It may not be a |
| // type, nor can it be an expression like |MOJO_ALIGNOF(type)| (due to the |
| // non-C++11 MSVS version). |
| #if __cplusplus >= 201103L |
| #define MOJO_ALIGNAS(alignment) alignas(alignment) |
| #elif defined(__GNUC__) |
| #define MOJO_ALIGNAS(alignment) __attribute__((aligned(alignment))) |
| #elif defined(_MSC_VER) |
| #define MOJO_ALIGNAS(alignment) __declspec(align(alignment)) |
| #else |
| #error "Please define MOJO_ALIGNAS() for your compiler." |
| #endif |
| |
| #endif // MOJO_PUBLIC_C_SYSTEM_MACROS_H_ |