[Boost-commit] svn:boost r42088 - sandbox/committee/LWG/examples

From: hinnant_at_[hidden]
Date: 2007-12-15 18:08:13

Author: hinnant
Date: 2007-12-15 18:08:12 EST (Sat, 15 Dec 2007)
New Revision: 42088
URL: http://svn.boost.org/trac/boost/changeset/42088

Log:
Another native_handle example.

Added:
   sandbox/committee/LWG/examples/native_handle2.cpp   (contents, props changed)

Added: sandbox/committee/LWG/examples/native_handle2.cpp
==============================================================================
--- (empty file)
+++ sandbox/committee/LWG/examples/native_handle2.cpp	2007-12-15 18:08:12 EST (Sat, 15 Dec 2007)
@@ -0,0 +1,42 @@
+#include <mutex>
+#include <pthread.h>
+
+template <class Thread>
+struct has_native_handle_type
+{
+	struct two {char x; char y;};
+	template <class U> static two  test(...);
+	template <class U> static char test(typename U::native_handle_type*);
+public:
+	static const bool value = sizeof(test<Thread>(0)) == 1;
+};
+
+// Set the priority ceiling of a POSIX mutex if possible
+
+template <class Mutex>
+typename stb::enable_if
+<
+    has_native_handle_type<Mutex>::value,
+    int
+>::type
+mutex_set_priority_ceiling(Mutex& mut, int priority)
+{
+    static_assert(stb::is_same<typename Mutex::native_handle_type, pthread_mutex_t*>::value,
+                  "Mutex::native_handle_type isn't a pthread_mutex_t*");
+    int old_priority;
+    pthread_mutex_setprioceiling(mut.native_handle(), priority, &old_priority);
+    return old_priority;
+}
+
+int main()
+{
+    std::mutex mut1;
+    mutex_set_priority_ceiling(mut1, 3);  // ok on Mac OS X
+    std::timed_mutex mut2;
+    mutex_set_priority_ceiling(mut2, 3);  // compile time error on Mac OS X
+};
+
+/*
+main.cpp: In function ‘int main()’:
+main.cpp:36: error: no matching function for call to ‘mutex_set_priority_ceiling(std::timed_mutex&, int)’
+*/