auto_ptr和operator void *（）; [英] auto_ptr and operator void*();
问题描述
为什么auto_ptr没有像这样的强制转换操作符有任何理由：
operator void *（）;
所以一个人可以很容易地测试auto_ptr为NULL ???
标准不会声明这样的运算符。
检查auto_ptr是否指向NULL的唯一方法是使用.get （）方法
？
马丁
Is there any reason why auto_ptr does not have the cast operator like this:
operator void* ();
So that one could easily test auto_ptr for NULL ???
Standard does not declare such operator.
Is the only way to check if auto_ptr points to NULL, is to use .get() method
?
Martin
推荐答案
Marcin Vorbrodt写道：
Marcin Vorbrodt wrote:
有没有什么理由说auto_ptr没有像这样的演员操作符：
operator void *（）;
所以那个可以很容易地测试auto_ptr是否为NULL ???
标准不会声明这样的运算符。
是检查auto_ptr是否指向NULL的唯一方法，就是使用.get（）
方法？
Is there any reason why auto_ptr does not have the cast operator like
this:
operator void* ();
So that one could easily test auto_ptr for NULL ???
Standard does not declare such operator.
Is the only way to check if auto_ptr points to NULL, is to use .get()
method ?
不。还有一个，但那更加丑陋。要打电话给opertator->在其
函数表中。我不知道什么是理由忽略操作员无效* ...
它可能出现在即将出版的C ++标准书中。但是
直到那时我想最好的是在comp.lang.c ++。moderated中询问。
实际上在这个设计上工作的人大多挂在那里，因为他们放弃了这个小组的b
由于巨量的巨魔和偏离主题的帖子。 IIRC I
已经读过auto_ptr如何成为今天的样子，但我不记得
关于失踪的任何内容。操作员布尔或无效*。
根据Herb Sutter的 http://www.gotw.ca/gotw/025.htm 这是Bill
Gibbons，Greg Colvin和Steve Rumsby已经敲定了auto_ptr。
-
WW aka Attila
Nope. There is another one, but that is uglier. To call opertator-> in its
function form. I dunno what is the rationale to leave out operator void*...
It might be present in the rationale in the upcoming C++ Standard book. But
until then I guess the best is to ask in comp.lang.c++.moderated. Guys who
actually worked on this design mostly hang out there because they gave up on
this group due to the sheer amount of trolls and off-topic posts. IIRC I
have read about how auto_ptr became what it is today, but I do not recall
talling anything about the "missing" operator bool or void*.
According to Herb Sutter in http://www.gotw.ca/gotw/025.htm it was Bill
Gibbons, Greg Colvin and Steve Rumsby who has finalized auto_ptr.
--
WW aka Attila
" Marcin Vorbrodt" < MV ***** @ eos.ncsu.edu>在消息中写道
news：bk ********** @ uni00nw.unity.ncsu.edu ...
"Marcin Vorbrodt" <mv*****@eos.ncsu.edu> wrote in message
news:bk**********@uni00nw.unity.ncsu.edu...
auto_ptr是否有任何理由没有像这样的演员
运算符：
operator void *（）;
这样可以很容易地测试auto_ptr为NULL ???
这将允许有人写：
auto_ptr< int> p（new int）;
删除p;
标准不声明此类运算符。
也不应该。 安全布尔是指安全布尔。成语会更好。
检查auto_ptr是否指向NULL的唯一方法是使用.get（）方法吗？
Is there any reason why auto_ptr does not have the cast
operator like this:
operator void* ();
So that one could easily test auto_ptr for NULL ???
This would allow someone to write:
auto_ptr<int> p(new int);
delete p;
Standard does not declare such operator.
Nor should it. A "safe bool" idiom would be better.
Is the only way to check if auto_ptr points to NULL, is to
use .get() method ?
据我所知，但这不能保证不会以另一种方式获得
。
Dave
As far as I know, but that''s not a guarantee that there isn''t
another way.
Dave
David B. Held写道：
David B. Held wrote:
" Marcin Vorbrodt" < MV ***** @ eos.ncsu.edu>在消息中写道
新闻：bk ********** @ uni00nw.unity.ncsu.edu ...
"Marcin Vorbrodt" <mv*****@eos.ncsu.edu> wrote in message
news:bk**********@uni00nw.unity.ncsu.edu...
auto_ptr是否有任何理由没有这样的演员
运算符：
operator void *（）;
这样可以很容易地测试auto_ptr为NULL ???
Is there any reason why auto_ptr does not have the cast
operator like this:
operator void* ();
So that one could easily test auto_ptr for NULL ???
这将允许有人写：
auto_ptr< int> p（new int）;
删除p;
This would allow someone to write:
auto_ptr<int> p(new int);
delete p;
是吗？你能删除一个空格*吗？删除操作符不会知道要使用什么析构函数（如果有的话），或者要释放的内存量
（除非它与...一起存储）以某种方式分配内存。
-Kevin
-
我的电子邮件地址有效，但会定期更改。
如需联系我，请使用最近发布的地址。
Would it? Can you delete a void *? The delete operator wouldn''t know
what destructor (if any) to use, or the amount of memory to be freed
(unless it''s stored with the allocated memory somehow).
-Kevin
--
My email address is valid, but changes periodically.
To contact me please use the address from a recent posting.
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