删除时将指针设置为null？ [英] Set a pointer to null when deleting?
问题描述
删除指针时，应将其设置为NULL，对吧？
Joe
< blockquote> Joe Van Dyk写道：
删除指针时，应将其设置为NULL，对吗？
不。你的指针应该总是超出范围，所以不要打扰
将它弄为空。
如果必须，请使用std :: auto_ptr或boost :: shared_ptr，并重置（NULL）
（如果我没记错的话）。
然后他们的秘密内部指针将只删除在他们离开
范围之前，他们将处理它的NULL。
-
Phlip http://www.greencheese.org/ZeekLand < - NOT a博客!!!
Joe Van Dyk写道：当你删除指针时，你应该把它设置为NULL，对吧？
不会。如果你删除一个指针，它可能是一个类成员，而且你是从b
中删除它析构函数。在这种情况下，你不要把它设置为0，
因为
没人会注意到。另一个常见的情况是在作业中，但是在这种情况下，你需要新的替换对象。 （你首先要做新b / b
，所以如果你的内存不足，分配失败，但
旧值不会丢失）。
当然，如果你使用智能指针，这都是自动的。
HTH，
Michiel Salters
Phlip写道：Joe Van Dyk写道：
删除指针时，应将其设置为NULL，对吗？
不。你的指针应该总是超出范围，所以不要打扰它。
胡说八道。如果我的指针是数据成员并且我正在管理自己的内存，那么在某些情况下我应该将它设置为空指针。删除后没有
必然超出范围。
如果必须，请使用std :: auto_ptr或boost :: shared_ptr，并重置（NULL）
那（如果我没记错的话）。
''提升''是非标准的。 ''std :: auto_ptr''由于其特定的复制语义而不适合某些
的情况。
[..]
V
-
请在通过电子邮件回复时删除资金''A'
我请不要回复最热门的回复，请不要问
When you delete a pointer, you should set it to NULL, right?
Joe
Joe Van Dyk wrote:
When you delete a pointer, you should set it to NULL, right?
No. Your pointer should always be about to go out of scope, so don''t bother
to NULL it.
If you must, use std::auto_ptr or boost::shared_ptr, and reset(NULL) that
(if I recall correctly).
Then their secret internal pointer will delete just before they go out of
scope, and they will take care of its NULL.
--
Phlip
http://www.greencheese.org/ZeekLand <-- NOT a blog!!!
Joe Van Dyk wrote:When you delete a pointer, you should set it to NULL, right?
No. If you delete a pointer, it''s probably a class member, and you''re
deleting it from a destructor. In that case, you don''t set it to 0,
because
noone will ever notice. The other common case is in assignments, but
in that case you will have new''ed a replacement object before. (You do
the new first, so if you run out of memory the assignment fails but the
old value is not lost).
Of course, if you use a smart pointer this is all automatic.
HTH,
Michiel Salters
Phlip wrote:Joe Van Dyk wrote:When you delete a pointer, you should set it to NULL, right?
No. Your pointer should always be about to go out of scope, so don''t
bother to NULL it.
Nonsense. If my pointer is a data member and I am managing my own
memory, I should set it to null pointer in some cases. It doesn''t
necessarily go out of scope right after deletion.
If you must, use std::auto_ptr or boost::shared_ptr, and reset(NULL)
that (if I recall correctly).
''boost'' is non-standard. ''std::auto_ptr'' is not suitable for some
cases due to its particular copy semantics.
[..]
V
--
Please remove capital ''A''s when replying by e-mail
I do not respond to top-posted replies, please don''t ask
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