// filename:c2011-7-17-7-4-ex.c
// original examples and/or notes:
// 		(c) ISO/IEC JTC1 SC22 WG14 N1570, April 12, 2011
// 			C2011 7.17.7.4 The atomic_compare_exchange generic functions
// compile and output mechanism:
// 		(c) Ogawa Kiyoshi, kaizen@gifu-u.ac.jp, December.29, 2013
// compile errors and/or wornings:
// 		(c) Apple LLVM version 4.2 (clang-425.0.27) (based on LLVM 3.2svn)
// 			Target: x86_64-apple-darwin11.4.2 //Thread model: posix
// 		(c) LLVM 2003-2009 University of Illinois at Urbana-Champaign.
// gcc-4.9 (GCC) 4.9.0 20131229 (experimental)
// Copyright (C) 2013 Free Software Foundation, Inc.
#include <stdio.h>
#include <string.h>
#include <stdatomic.h>

char * function ( char * add){ return add;};

int main(void)
{
	
        char object[] = "\0abc\0de";      
        char expected[] = "\0abc\0de";
        char desired[] = "\0abcdef";
	
	char * exp=object, * cur=expected, * des=desired;
	
if (memcmp(object, expected, sizeof (*object)) == 0)
	memcpy(object, &desired, sizeof (*object));
else
	memcpy(expected, object, sizeof (*object));
// Example
exp = atomic_load(&cur);
do {
		des = function(exp);
} while (!atomic_compare_exchange_weak(&cur, &exp, des));
	
return printf("7.17.7.4 The atomic_compare_exchange generic functions %d\n", exp);
}
// output may be 
// 7.17.7.4 The atomic_compare_exchange generic functions 1476647632