C源文件：
1 static int 2 get_callback(zpool_handle_t *zhp, void *data) 3 { 4 zprop_get_cbdata_t *cbp = (zprop_get_cbdata_t *)data; 5 char value[MAXNAMELEN]; 6 zprop_source_t srctype; 7 zprop_list_t *pl; 8 9 for (pl = cbp->cb_proplist; pl != NULL; pl = pl->pl_next) { 10 11 /* 12 * Skip the special fake placeholder. This will also skip 13 * over the name property when ‘all‘ is specified. 14 */ 15 if (pl->pl_prop == ZPOOL_PROP_NAME && 16 pl == cbp->cb_proplist) 17 continue; 18 19 if (pl->pl_prop == ZPROP_INVAL && 20 (zpool_prop_feature(pl->pl_user_prop) || 21 zpool_prop_unsupported(pl->pl_user_prop))) { 22 srctype = ZPROP_SRC_LOCAL; 23 24 if (zpool_prop_get_feature(zhp, pl->pl_user_prop, 25 value, sizeof (value)) == 0) { 26 zprop_print_one_property(zpool_get_name(zhp), 27 cbp, pl->pl_user_prop, value, srctype, 28 NULL, NULL); 29 } 30 } else { 31 if (zpool_get_prop(zhp, pl->pl_prop, value, 32 sizeof (value), &srctype) != 0) 33 continue; 34 35 zprop_print_one_property(zpool_get_name(zhp), cbp, 36 zpool_prop_to_name(pl->pl_prop), value, srctype, 37 NULL, NULL); 38 } 39 } 40 return (0); 41 } 42 来源 -- illumos/usr/src/cmd/zpool/zpool_main.c
上面代码中：value定义的是数组char value[MAXNAMELEN];，我采用的方法如下：
1 value = c_char * 256 2 3 libzfs.zpool_get_prop(zhp, prop, value, 256, byref(srctype))
采用上述方法时，当运行到libzfs.zpool_get_prop时，直接显示为None
正确的方法为：
1 value = create_string_buffer(256) 2 3 ret = libzfs.zpool_get_prop(zhp, prop, value, 256, byref(srctype))
采用create_string_buffer才能正确显示
执行命令：print(type(value))
print(dir(value))
显示如下：
<class ‘ctypes.c_char_Array_256‘>
[‘__class__‘, ‘__ctypes_from_outparam__‘, ‘__delattr__‘, ‘__delitem__‘, ‘__dict__‘, ‘__doc__‘, ‘__eq__‘, ‘__format__‘, ‘__ge__‘, ‘__getattribute__‘, ‘__getitem__‘, ‘__gt__‘, ‘__hash__‘, ‘__init__‘, ‘__le__‘, ‘__len__‘, ‘__lt__‘, ‘__module__‘, ‘__ne__‘, ‘__new__‘, ‘__reduce__‘, ‘__reduce_ex__‘, ‘__repr__‘, ‘__setattr__‘, ‘__setitem__‘, ‘__setstate__‘, ‘__sizeof__‘, ‘__str__‘, ‘__subclasshook__‘, ‘__weakref__‘, ‘_b_base_‘, ‘_b_needsfree_‘, ‘_length_‘, ‘_objects‘, ‘_type_‘, ‘raw‘, ‘value‘]
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原文地址：http://www.cnblogs.com/fendou-999/p/3830240.html
