[cpp] support rt-thread CPP wrapper sub-switch macros

components/libc/cplusplus/os/cxx_mutex.h

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2016/10/1      Bernard      The first version
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <rtthread.h>
+
+namespace rtthread {
+
+/** The Mutex class is used to synchronise the execution of threads.
+ This is for example used to protect access to a shared resource.
+*/
+class Mutex {
+public:
+    /** Create and Initialize a Mutex object */
+    Mutex(const char *name = "mutex");
+    ~Mutex();
+
+    /** Wait until a Mutex becomes available.
+      @param   millisec  timeout value or 0 in case of no time-out. (default: WaitForever)
+      @return  true if the mutex was acquired, false otherwise.
+     */
+    bool lock(int32_t millisec = -1);
+
+    /** Try to lock the mutex, and return immediately
+      @return  true if the mutex was acquired, false otherwise.
+     */
+    bool trylock();
+
+    /** Unlock the mutex that has previously been locked by the same thread
+     */
+    void unlock();
+
+private:
+    struct rt_mutex mID;
+};
+
+}