const对静态只读的优势？ [英] Advantage of const against static readonly?

问题描述

我想知道使用const而不是静态只读的好处是什么。


静态只读是运行时常量，可以在初始化程序中设置一次

或静态ctor，而const遭受二进制不兼容

，因为它被硬化为二进制文件。


我不相信有性能优势使用const over

静态只读，因为JIT会考虑到这一点，或者我错了吗？

Iam wondering what the benefit of using const over static readonly is.

static readonly is a runtime constant and can be set once in the initializer
or the static ctor, whereas const is suffering from binary incompatibility
since it is hardbaked into the binary.

I do not believe there is a performance advantage with using const over
static readonly since the JIT will take account of that or am I wrong here?

推荐答案

一个值得注意的区别是，由于它们没有加载到内存中，因此它们不会消耗任何内存，因为它们不会被加载到内存中。


Mattias


-

Mattias Sj？gren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com

请回复到新闻组。

One notable difference is that consts don''t consume any memory at
runtime since they aren''t loaded into memory.

Mattias

--
Mattias Sj?gren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.

你不担心静态只读值的内存消耗

由于它的存在而只存在一次静态性质，你是:)

不是相反的情况：如果你的const是一个相当大的结构，它将在每个使用这个库的二进制文件中硬烘烤。

我怀疑JIT会生成const和静态readonly

完全相同的代码，因为我无法想象为什么我不会这样的原因

可以通过这种方式优化代码。


" Mattias Sj？gren" <毫安******************** @ mvps.org> schrieb im Newsbeitrag

新闻：％2 ****************** @ tk2msftngp13.phx.gbl ...

You aren''t worried about the memory consumption of a static readonly value
which exists exactly one time due to its static nature, are you :)
No the opposite is the case: If your const is a rather large struct it will
be hardbaked in each binary which uses this library.
I suspect that the JIT will generate both both const and static readonly
exactly the same code as I cannot imagine a reason why I would not be
possible to optimize the code this way.

"Mattias Sj?gren" <ma********************@mvps.org> schrieb im Newsbeitrag
news:%2******************@tk2msftngp13.phx.gbl...

一个值得注意的区别是，它们不会在运行时消耗任何内存，因为它们不会被加载到内存中。

Mattias

-
Mattias Sj？gren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
请仅回复新闻组。

One notable difference is that consts don''t consume any memory at
runtime since they aren''t loaded into memory.

Mattias

--
Mattias Sj?gren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.

const'的值必须在编译时进行评估，而readonly'的

值可以设置在运行时在类的构造函数中。这意味着

const只能是任何原始类型或字符串，

而readonly字段可以是任何类型。


每次实例化

类时，只读字段可以为其分配不同的值，每个对象的const字段具有相同的值

已创建。


/ Joakim


cody写道：

A const''s value must be valuated at compile time, whereas a readonly''s
value can be set at runtime in the constructor of the class. This means
that a const can only be of any of the primitive types or a string,
whereas a readonly field can be of any type.

A readonly field can have different values assigned to it every time the
class is instantiated, a const field has the same value for every object
created.

/Joakim

cody wrote:

我想知道使用const比静态readonly有什么好处是静态readonly是一个运行时常量，可以在初始化程序中设置一次
或静态ctor，而const则存在二进制不兼容性，因为它被硬化为二进制文件。

我不认为使用const over
static readonly会有性能优势，因为JIT会考虑到这一点，或者我在这里错了吗？

Iam wondering what the benefit of using const over static readonly is.

static readonly is a runtime constant and can be set once in the initializer
or the static ctor, whereas const is suffering from binary incompatibility
since it is hardbaked into the binary.

I do not believe there is a performance advantage with using const over
static readonly since the JIT will take account of that or am I wrong here?

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