NULL指针解除引用 [英] NULL Pointer Dereference
问题描述
你好eveyone。
什么是空指针解除引用？我尝试搜索谷歌，但
返回的唯一结果是错误报告。一些示例代码，如果
可能，也会受到赞赏。
提前致谢。
----- =通过Newsfeeds.Com发布，未经审查的Usenet新闻= -----
http：// www .newsfeeds.com - 世界排名第一的新闻组服务！
----- ==超过80,000个新闻组--16个不同的服务器！ = -----
Hello eveyone.
What exactly is a NULL Pointer Dereference? I tried searching google but
the only results that returned were bug reports. Some example code, if
possible, would also be appreciated.
Thanks in advance.
-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 80,000 Newsgroups - 16 Different Servers! =-----
推荐答案
" Denis Palmeiro" <恩******* @ gta.igs.net>在消息新闻中写道：pa **************************** @ gta.igs.net ...
"Denis Palmeiro" <en*******@gta.igs.net> wrote in message news:pa****************************@gta.igs.net...
你好eveyone。
什么是NULL指针解除引用？我尝试搜索谷歌，但
返回的唯一结果是错误报告。一些示例代码，如果可能的话，也将受到赞赏。
Hello eveyone.
What exactly is a NULL Pointer Dereference? I tried searching google but
the only results that returned were bug reports. Some example code, if
possible, would also be appreciated.
int * p = 0;
* p; //解除引用空指针
-
Jun，Woong（my******@hanmail.net）
部门大学物理系首尔
int *p = 0;
*p; // dereferencing a null pointer
--
Jun, Woong (my******@hanmail.net)
Dept. of Physics, Univ. of Seoul
是的，那就是我们如何取消引用指针。取消引用它们，产生它们指向的实际数据。
通常，NULL被认为是错误条件。就像
指针没有指向任何地方。
要声明使用NULL指针，
int * intPtr = （int *）NULL; / * NULL定义为0 * /
删除NULL指针可能导致非法操作......我不确定
sumit
" Jun Woong" <我的****** @ hanmail.net>在消息新闻中写道：< be ********** @ news.hananet.net> ...
Yes, that''s how we dereferenc pointer. Dereferencing them, yields tha
actual data they point to.
Generally, NULL is considered to be a error condition. Like the
pointer is not pointing anywhere.
To declare NULL pointer use,
int * intPtr = (int *) NULL; /* NULL is defined as 0 */
Dereferncing NULL pointer may cause illegal operation...I am not sure
sumit
"Jun Woong" <my******@hanmail.net> wrote in message news:<be**********@news.hananet.net>...
" Denis Palmeiro" <恩******* @ gta.igs.net>在消息新闻中写道：pa **************************** @ gta.igs.net ...
"Denis Palmeiro" <en*******@gta.igs.net> wrote in message news:pa****************************@gta.igs.net...
你好eveyone。
什么是NULL指针解除引用？我尝试搜索谷歌，但
返回的唯一结果是错误报告。一些示例代码，如果可能的话，也将受到赞赏。
Hello eveyone.
What exactly is a NULL Pointer Dereference? I tried searching google but
the only results that returned were bug reports. Some example code, if
possible, would also be appreciated.
int * p = 0;
* p; //解除引用空指针
int *p = 0;
*p; // dereferencing a null pointer
2003年7月8日07:13:19 -0700， su ********** @ wipro.com 写道：
On 8 Jul 2003 07:13:19 -0700, su**********@wipro.com wrote:
是的，那是'我们如何取消引用指针。取消引用它们，可以得出它们指向的实际数据。
通常，NULL被认为是错误条件。就像
指针没有指向任何地方。
要声明NULL指针使用，
int * intPtr =（int *）NULL; / * NULL定义为0 * /
取消空指针可能导致非法操作......我不确定
sumit
Yes, that''s how we dereferenc pointer. Dereferencing them, yields tha
actual data they point to.
Generally, NULL is considered to be a error condition. Like the
pointer is not pointing anywhere.
To declare NULL pointer use,
int * intPtr = (int *) NULL; /* NULL is defined as 0 */
Dereferncing NULL pointer may cause illegal operation...I am not sure
sumit
请不要发帖。我实际上认为Jun的帖子是一个
正确答案。你的帖子有一些奇怪的结构。例如，
您不需要显式地转换NULL。
NULL是stddef.h中定义的宏。空指针常量。
空指针常量是一个整数常量表达式，
值为0或这样的表达式转换为void *。空指针
常量转换为指针类型称为空指针。
#include< stddef.h>
int * ip = NULL;
* ip; //未定义的行为
就足够了。 derefencing空指针的问题是
它调用未定义的行为。不可能知道任何特定实现将如何处理它。
祝福，
鲍勃
Please do not top post. I actually thought that Jun''s post was a
correct answer. Your post has some odd constructions. For example,
you do not need to cast NULL explicitly.
NULL is a macro defined in stddef.h. to be the null pointer constant.
A null pointer constant is an integer constant expression with the
value 0 or such an expression casted to void*. A null pointer
constant converted to a pointer type is called a null pointer.
#include <stddef.h>
int* ip = NULL;
*ip; // undefined behavior
would be sufficient. The problem with derefencing a null pointer is
that it invokes undefined behavior. It is impossible to know how any
particular implementation will handle it.
Best wishes,
Bob
这篇关于NULL指针解除引用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
