本地var的任何原因是“静态const”？ [英] Any reason for local var to be "static const"?

问题描述

查看一些代码，我在一个函数中看到一个声明，如


static const string s（some string）;


静态是否有任何用途？

解决方案

2006年9月6日12:37:08 -0700 in comp.lang。 c ++，Chris

< ch *************** @ gmail.comwrote，

>看一些代码，我在一个函数中看到一个声明，如

静态const字符串s（some string）;

静态服务是否为任何目的在这里？

防止每次调用

函数再次构造字符串。

Chris写道：

查看一些代码我在一个函数中看到一个声明，如


静态const字符串s（一些字符串）;


静态服务在这里有用吗？

是的，静态有用。静态自动变量创建

一次，当函数退出时不会被销毁。变量s只构造一次

。我猜这段代码的代表正在尝试

通过使其静态来提高性能。


-Brian

BigBrian写道：

Chris写道：

查看一些代码我在一个函数中看到一个声明，如


static const string s（some string）;


静态是否适用于此目的？

是的，静态有用。静态自动变量创建

一次，当函数退出时不会被销毁。变量s只构造一次

。我猜这段代码的代表正在尝试

来提高性能，使其保持静态。


-Brian

如果是静态的话不存在它只是声明为const，

编译器是否可能做同样的事情 - 在某处分配字符串

并重用它？只是想知道静电是否在实践中是否过度杀伤。

Looking at some code I see a declaration inside a function like

static const string s("some string");

Does the static serve any purpose here?

解决方案

On 6 Sep 2006 12:37:08 -0700 in comp.lang.c++, "Chris"
<ch***************@gmail.comwrote,

>Looking at some code I see a declaration inside a function like

static const string s("some string");

Does the static serve any purpose here?

Prevents the string from being constructed over again for every call
of the function.

Chris wrote:

Looking at some code I see a declaration inside a function like

static const string s("some string");

Does the static serve any purpose here?

Yes, static serves a purpose. Static automatic variables are created
once and aren''t destroyed when the function exits. The variable s is
only constructed once. I would guess the writter of the code is trying
to improve performance by making it static.

-Brian

BigBrian wrote:

Chris wrote:

Looking at some code I see a declaration inside a function like

static const string s("some string");

Does the static serve any purpose here?

Yes, static serves a purpose. Static automatic variables are created
once and aren''t destroyed when the function exits. The variable s is
only constructed once. I would guess the writter of the code is trying
to improve performance by making it static.

-Brian

If "static" weren''t there and it was just declared "const", would the
compiler be likely to do the same thing--allocate the string once
somewhere and reuse it? Just wondering if the static is overkill in
practice.

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