无效*问题 [英] void* question
问题描述
使用void *的主要原因是什么？
我们什么时候应该对输入参数和返回值使用void *？
我们如何转换void *指向我们需要的类型？
Thanx
Janice写道：什么是使用void *的主要原因是什么？
如果你不知道指向的
对象的实际类型，或者不关心它是什么，请使用`void *''或者
希望隐藏它。
我们什么时候应该对输入参数和返回值使用void *？
当参数和返回值都符合上述一个或多个标准时，
我们怎样才能投出void *指向我们需要的类型的指针？
投射任何东西的唯一方法是使用强制转换操作符。
转换`void *''到'int *''，比方说，使用`（int *）voidptr''。
也许你会给出一些更详细的信息'' s
让你感到困惑，我能够更清楚地解释。
-
Er ********* @ sun.com
Eric Sosman< er ********* @ sun.com>写道：
Janice写道：我们如何将void *指针转换为我们需要的类型？
投射任何东西的唯一方法是使用强制转换操作符。
要将`void *''转换为`int *''，请使用`（int *）voidptr''。
这是真的，但不是很有帮助。施放到void *之前通常不需要
，因为
void *和其他指向对象或不完整类型的指针之间的转换不会
需要演员表。
-
大笔资金往往能解除我可能遇到的任何顾忌。
- Stephan Wilms
Eric Sosman< er ********* @ sun.com>这样说：
也许如果你能详细说明令你困惑的是什么，我就能更清楚地解释一下。 / blockquote>
恕我直言，这听起来像是家庭作业，所以也许你做得很好......
-
Christopher Benson-Manica |我*应该*知道我在说什么 - 如果我
ataru（at）cyberspace.org |不，我需要知道。火焰欢迎。
What is the major reason for using void*?
When should we use void* for both input arguments and return value?
How can we cast the void* pointer to the type we need?
Thanx解决方案Janice wrote:What is the major reason for using void*?
Use a `void*'' when you do not know the pointed-to
object''s actual type, or do not care what it is, or
wish to conceal it.
When should we use void* for both input arguments and return value?
When both the arguments and the returned value meet
one or more of the criteria above.
How can we cast the void* pointer to the type we need?
The only way to cast anything is with a cast operator.
To convert a `void*'' to an `int*'', say, use `(int*)voidptr''.
Perhaps if you''d give a little more detail about what''s
puzzling you, I''d be able to explain more clearly.
--
Er*********@sun.com
Eric Sosman <er*********@sun.com> writes:
Janice wrote:How can we cast the void* pointer to the type we need?
The only way to cast anything is with a cast operator.
To convert a `void*'' to an `int*'', say, use `(int*)voidptr''.
This is literally true, but not very helpful. It is not usually
necessary to cast to or from void * because conversions between
void * and other pointers to object or incomplete type do not
require casts.
--
"Large amounts of money tend to quench any scruples I might be having."
-- Stephan Wilms
Eric Sosman <er*********@sun.com> spoke thus:
Perhaps if you''d give a little more detail about what''s
puzzling you, I''d be able to explain more clearly.
IMHO it sounds like homework, so maybe you did just fine...
--
Christopher Benson-Manica | I *should* know what I''m talking about - if I
ataru(at)cyberspace.org | don''t, I need to know. Flames welcome.
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