原来bzero()是这个功能，学习啦。下面的文章可以好好参考，出处：http://hi.baidu.com/wg_wang/item/5fa42c15c73b8efa9c778af8
bzero & memset置零的性能比较
}
}
运行结果：
array size: 1 bzero time: 28 memset time: 1 bzero>memset?: 1
array size: 2 bzero time: 1 memset time: 1 bzero>memset?: 0
array size: 4 bzero time: 1 memset time: 1 bzero>memset?: 0
array size: 8 bzero time: 1 memset time: 1 bzero>memset?: 0
array size: 16 bzero time: 1 memset time: 1 bzero>memset?: 0
array size: 32 bzero time: 1 memset time: 1 bzero>memset?: 0
array size: 64 bzero time: 1 memset time: 0 bzero>memset?: 1
array size: 128 bzero time: 1 memset time: 1 bzero>memset?: 0
array size: 256 bzero time: 1 memset time: 1 bzero>memset?: 0
array size: 512 bzero time: 1 memset time: 1 bzero>memset?: 0
array size: 1024 bzero time: 1 memset time: 1 bzero>memset?: 0
array size: 2048 bzero time: 1 memset time: 1 bzero>memset?: 0
array size: 4096 bzero time: 2 memset time: 2 bzero>memset?: 0
array size: 8192 bzero time: 2 memset time: 2 bzero>memset?: 0
array size: 16384 bzero time: 5 memset time: 6 bzero>memset?: 0
array size: 32768 bzero time: 9 memset time: 8 bzero>memset?: 1
array size: 65536 bzero time: 27 memset time: 24 bzero>memset?: 1
array size: 131072 bzero time: 81 memset time: 68 bzero>memset?: 1
array size: 262144 bzero time: 190 memset time: 169 bzero>memset?: 1
array size: 524288 bzero time: 447 memset time: 393 bzero>memset?: 1
array size: 1048576 bzero time: 996 memset time: 973 bzero>memset?: 1
array size: 2097152 bzero time: 2258 memset time: 2272 bzero>memset?: 0
array size: 4194304 bzero time: 4821 memset time: 4799 bzero>memset?: 1
array size: 8388608 bzero time: 9797 memset time: 9799 bzero>memset?: 0
array size: 16777216 bzero time: 19764 memset time: 19737 bzero>memset?: 1
array size: 33554432 bzero time: 39687 memset time: 39675 bzero>memset?: 1
array size: 67108864 bzero time: 79907 memset time: 79324 bzero>memset?: 1
array size: 134217728 bzero time: 158956 memset time: 158775 bzero>memset?: 1
array size: 268435456 bzero time: 318247 memset time: 318632 bzero>memset?: 0
array size: 536870912 bzero time: 638536 memset time: 638883 bzero>memset?: 0