选择函数参数类型 - 指针或对象？ [英] Choosing function parameter types - pointers or objects?

问题描述

目前，我只编写接受指针作为

参数的函数来改变一个值，但我已经意识到它经常是

是一个通过指针而不是实际的

对象更有效率。

我知道这个问题有点模糊，但我想知道任何

规则/指南/样式问题，何时使用指针，何时

不要，在你的函数参数中？


我也是对任何灰色区域感兴趣，甚至是像win32 API中那样编写了关于
的非主题函数，但我怀疑

其他人是谁。


干杯，马特

解决方案

ballpointpenthief说：

我知道这个问题有点模糊，但是我想知道任何
规则/指南/样式问题，什么时候使用指针，什么时候
不在你的函数参数中？


如果它是原生类型（int，short，long，double，那种东西），除非你以原样传递

需要破解它的价值。还有别的东西 - 结构和

东西 - 传递指针。


-

Richard Heathfield

Usenet是一个奇怪的地方 - dmr 29/7/1999
http://www.cpax.org.uk

电子邮件：rjh在上面的域名（但显然放弃了www）

ballpointpenthief张贴：

我知道这个问题有点模糊，但我想知道任何
规则/指南/风格问题，什么时候使用指针，什么时候
不要，在你的函数参数？

你将得到的效率：


（1）按值传递对象（因此在过程中复制它。


和


（2）传递其地址，并取消引用地址。

对于内在类型，（1）更快。


对于一个巨大的类型，其对象可能是千字节，（2）将是

更快。

我相信其他人可以给你更详细的回复。


-


弗雷德erick Gotham

Richard Heathfield< in ***** @ invalid.invalid>写道：

ballpointpenthief说：

我知道这个问题有点模糊，但我想知道任何
规则/指南/风格问题，对于什么时候来说在你的函数参数中使用指针，什么时候不用？

如果它是本机类型（int，short，long，double，那种东西） ，除非你需要破解它的价值，否则将其传递给原始版本。还有其他东西 - 结构和
东西 - 传递一个指针。

我不会毫不犹豫地直接传递* small *结构。


-

Keith Thompson（The_Other_Keith） ks *** @ mib.org < http://www.ghoti.net/~kst>

圣地亚哥超级计算机中心< *> < http://users.sdsc.edu/~kst>

我们必须做点什么。这是事情。因此，我们必须这样做。

At the moment, I only write functions which accept pointers as
arguments in order to change a value, but I''ve realised it would often
be a lot more effiecient to pass a pointer rather than an actual
object.
I know this question is a bit vague, but I was wondering about any
rules / guidelines / style issues, for when to use pointers, and when
not to, in your function parameters?

I''m also interested in any grey areas, or even off-topic functions that
have been written like in the win32 API for instance, but I doubt
anyone else is.

Cheers, Matt

解决方案

ballpointpenthief said:

I know this question is a bit vague, but I was wondering about any
rules / guidelines / style issues, for when to use pointers, and when
not to, in your function parameters?

If it''s a native type (int, short, long, double, that sort of thing), pass
it in raw unless you need to hack its value. Anything else - structs and
stuff - pass a pointer.

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at above domain (but drop the www, obviously)

ballpointpenthief posted:

I know this question is a bit vague, but I was wondering about any
rules / guidelines / style issues, for when to use pointers, and when
not to, in your function parameters?

You''d have the measure the efficiency of:

(1) Passing the object by value (thus copying it in the process).

and

(2) Passing its address, and dereferencing the address.
For the intrinsic types, (1) is faster.

For a huge type, an object of which is perhaps a kilobyte, (2) would be
faster.
I''m sure the others can give you a more detailed reply.

--

Frederick Gotham

Richard Heathfield <in*****@invalid.invalid> writes:

ballpointpenthief said:

I know this question is a bit vague, but I was wondering about any
rules / guidelines / style issues, for when to use pointers, and when
not to, in your function parameters?

If it''s a native type (int, short, long, double, that sort of thing), pass
it in raw unless you need to hack its value. Anything else - structs and
stuff - pass a pointer.

I wouldn''t hesitate to pass a *small* structure directly.

--
Keith Thompson (The_Other_Keith) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

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