| // 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> |
| |
| #if !defined(__cplusplus) |
| #include <assert.h> // Defines static_assert() in C11. |
| #include <stdalign.h> // Defines alignof() in C11. |
| #endif |
| |
| // Assert things at compile time. (|msg| should be a valid identifier name.) |
| // Use like: |
| // MOJO_STATIC_ASSERT(sizeof(struct Foo) == 12, "Foo has invalid size"); |
| #define MOJO_STATIC_ASSERT(expr, msg) static_assert(expr, msg) |
| |
| // Defines a pointer-sized struct field of the given type. This ensures that the |
| // field has an 8-byte footprint on both 32-bit and 64-bit systems, using an |
| // anonymous bitfield of either 32 or 0 bits, depending on pointer size. |
| // clang-format off |
| #define MOJO_POINTER_FIELD(type, name) \ |
| type name; \ |
| uint32_t : (sizeof(void*) == 4 ? 32 : 0) |
| // clang-format on |
| |
| // Like the C++11 |alignof| operator. |
| #define MOJO_ALIGNOF(type) alignof(type) |
| |
| // 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). |
| // This can't use alignas() in C11 mode because unlike the C++11 version the |
| // C11 version can't be used on struct declarations. |
| #if defined(__cplusplus) |
| #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_ |