// Copyright 2014 The Chromium Authors // 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> #include <stdint.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) … // 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) … // clang-format on // Like the C++11 |alignof| operator. #define MOJO_ALIGNOF(type) … // Provides a convenient test for the presence of a field in a user-provided // structure from a potentially older version of the ABI. Presence is determined // by comparing the struct's provided |struct_size| value against the known // offset and size of the field in this version of the ABI. Because fields are // never reordered or removed, this is a sufficient test for the field's // presence within whatever version of the ABI the client is programmed against. #define MOJO_IS_STRUCT_FIELD_PRESENT(struct_pointer, field) … // 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) … #elif defined(__GNUC__) #define MOJO_ALIGNAS … #elif defined(_MSC_VER) #define MOJO_ALIGNAS … #else #error "Please define MOJO_ALIGNAS() for your compiler." #endif #endif // MOJO_PUBLIC_C_SYSTEM_MACROS_H_
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