mutex (try_lock): Do not swallow exceptions.

	* include/std/mutex (try_lock): Do not swallow exceptions.
	* testsuite/30_threads/try_lock/4.cc: Fix test.

From-SVN: r215467

libstdc++-v3/ChangeLog

 2014-09-22  Jonathan Wakely  <jwakely@redhat.com>
 
+	* include/std/mutex (try_lock): Do not swallow exceptions.
+	* testsuite/30_threads/try_lock/4.cc: Fix test.
+
+2014-09-22  Jonathan Wakely  <jwakely@redhat.com>
+
 	PR libstdc++/54316
 	PR libstdc++/53626
 	* config/abi/pre/gnu.ver: Add new exports.

libstdc++-v3/include/std/mutex

@@ -630,12 +630,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     {
       int __idx;
       auto __locks = std::tie(__l1, __l2, __l3...);
-      __try
-      { __try_lock_impl<0>::__do_try_lock(__locks, __idx); }
-      __catch(const __cxxabiv1::__forced_unwind&)
-      { __throw_exception_again; }
-      __catch(...)
-      { }
+      __try_lock_impl<0>::__do_try_lock(__locks, __idx);
       return __idx;
     }
 

libstdc++-v3/testsuite/30_threads/try_lock/4.cc

@@ -133,8 +133,15 @@ void test03()
       while (unreliable_lock::throw_on < 3)
       {
         unreliable_lock::count = 0;
-        int failed = std::try_lock(l1, l2, l3);
-        VERIFY( failed == unreliable_lock::throw_on );
+        try
+          {
+            std::try_lock(l1, l2, l3);
+            VERIFY( false );
+          }
+        catch (int e)
+          {
+            VERIFY( e == unreliable_lock::throw_on );
+          }
         ++unreliable_lock::throw_on;
       }
     }