sys: Added basic C++ compat for C11 atomics

Added a header to allow defining C interfaces using the default C11 atomic types. Those types are however fully opaque and inaccessible from C++, as C11 atomics are completely incompatible with C++.
2024-12-29 04:50:03 +01:00 · 2019-10-22 23:08:11 +02:00 · 2019-10-22 23:08:11 +02:00 · cd8562e8c0
commit cd8562e8c0
parent a4e4c43203
1 changed files with 437 additions and 0 deletions
--- a/sys/include/c11_atomics_compat.hpp
+++ b/sys/include/c11_atomics_compat.hpp
@ -0,0 +1,437 @@
+/*
+ * Copyright (C) 2019 Otto-von-Guericke-Universität Magdeburg
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @defgroup    sys_c11_atomics_cpp_compat C++ compatibility with C11 atomics
+ * @ingroup     sys
+ * @brief       C++ compatibility of default C11 atomics types
+ *
+ * This module provides opaque `typedef`s for each standard C11 atomic type with
+ * the same size and alignment requirements. The contents of types are not
+ * accessible to C++ code, but this allows `struct`s to be defined with the
+ * same memory layout as the C version, so that they can be allocated from C++.
+ *
+ * @{
+ *
+ * @file
+ * @brief       C++ compatibility of default C11 atomics types
+ *
+ * @author      Marian Buschsieweke <marian.buschsieweke@ovgu.de>
+ */
+
+#pragma once
+
+#include "c11_atomics_compat_cpu.hpp"
+
+/**
+ * @brief   Initialize an atomic variable
+ *
+ * Usage (same syntax as the real C11 atomic initializer):
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * atomic_int foo = ATOMIC_VAR_INIT(42);
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+#define ATOMIC_VAR_INIT(x) { x }
+
+/**
+  * @brief Type with the same alignment and size as `atomic_bool`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_BOOL_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_bool;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_char`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_CHAR_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_char;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_schar`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_SCHAR_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_schar;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_uchar`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_UCHAR_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_uchar;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_short`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_SHORT_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_short;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_ushort`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_USHORT_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_ushort;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_int`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_INT_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_int;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_uint`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_UINT_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_uint;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_long`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_LONG_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_long;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_ulong`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_ULONG_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_ulong;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_llong`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_LLONG_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_llong;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_ullong`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_ULLONG_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_ullong;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_int_least8_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_INT_LEAST8_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_int_least8_t;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_uint_least8_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_UINT_LEAST8_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_uint_least8_t;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_int_least16_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_INT_LEAST16_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_int_least16_t;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_uint_least16_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_UINT_LEAST16_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_uint_least16_t;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_int_least32_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_INT_LEAST32_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_int_least32_t;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_uint_least32_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_UINT_LEAST32_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_uint_least32_t;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_int_least64_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_INT_LEAST64_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_int_least64_t;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_uint_least64_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_UINT_LEAST64_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_uint_least64_t;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_int_fast8_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_INT_FAST8_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_int_fast8_t;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_uint_fast8_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_UINT_FAST8_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_uint_fast8_t;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_int_fast16_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_INT_FAST16_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_int_fast16_t;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_uint_fast16_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_UINT_FAST16_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_uint_fast16_t;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_int_fast32_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_INT_FAST32_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_int_fast32_t;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_uint_fast32_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_UINT_FAST32_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_uint_fast32_t;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_int_fast64_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_INT_FAST64_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_int_fast64_t;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_uint_fast64_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_UINT_FAST64_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_uint_fast64_t;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_intptr_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_INTPTR_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_intptr_t;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_uintptr_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_UINTPTR_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_uintptr_t;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_size_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_SIZE_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_size_t;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_intmax_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_INTMAX_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_intmax_t;
+
+/**
+  * @brief Type with the same alignment and size as `atomic_uintmax_t`
+ */
+typedef struct {
+    /**
+     * @brief Opaque content placeholder
+     *
+     * Access only for initializing from C++
+     */
+    ATOMIC_UINTMAX_T_SAME_SIZED_TYPE do_not_access_from_cpp;
+} atomic_uintmax_t;
+
+/** @} */