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source/common/putilimp.h

 /*
 ******************************************************************************
 *
-*   Copyright (C) 1997-2014, International Business Machines
+*   Copyright (C) 1997-2015, International Business Machines
 *   Corporation and others.  All Rights Reserved.
 *
 ******************************************************************************
 *
 *  FILE NAME : putilimp.h
 *
 *   Date        Name        Description
 *   10/17/04    grhoten     Move internal functions from putil.h to this file.
 ******************************************************************************
 */
@@ skipping 207 matching lines @@
     /* U_HAVE_ATOMIC is typically set by an autoconf test of #include <atomic>  */
     /*   Can be set manually, or left undefined, on platforms without autoconf. */
 #   if defined(U_HAVE_ATOMIC) &&  U_HAVE_ATOMIC 
 #      define U_HAVE_STD_ATOMICS 1
 #   else
 #      define U_HAVE_STD_ATOMICS 0
 #   endif
 #endif
 
 
+/**
+ *  \def U_HAVE_CLANG_ATOMICS
+ *  Defines whether Clang c11 style built-in atomics are avaialable.
+ *  These are used in preference to gcc atomics when both are available.
+ */
+#ifdef U_HAVE_CLANG_ATOMICS
+    /* Use the predefined value. */
+#elif !defined(__clang__)
+#    define U_HAVE_CLANG_ATOMICS 0
+#else
+#if __has_builtin(__c11_atomic_load) && \
+    __has_builtin(__c11_atomic_store) && \
+    __has_builtin(__c11_atomic_fetch_add) && \
+    __has_builtin(__c11_atomic_fetch_sub)
+#    define U_HAVE_CLANG_ATOMICS 1
+#else
+#    define U_HAVE_CLANG_ATOMICS 0
+#endif
+#endif
+
 /*===========================================================================*/
 /** @{ Code alignment                                                        */
 /*===========================================================================*/
 
 /**
  * \def U_ALIGN_CODE
  * This is used to align code fragments to a specific byte boundary.
  * This is useful for getting consistent performance test results.
  * @internal
  */
@@ skipping 366 matching lines @@
 /* also _C_TS_calloc(x) */
 #else
 /* C defaults */
 # define uprv_default_malloc(x) malloc(x)
 # define uprv_default_realloc(x,y) realloc(x,y)
 # define uprv_default_free(x) free(x)
 #endif
 
 
 #endif