为什么？为什么？为什么？模板实施不足 [英] Why? Why? Why? insufficient template implementation

问题描述

我只是想知道。经过这么多年的工作后，为什么微软还没有看到完全适合完全实现C ++标准的模板部分呢？
许多其他供应商，无论是免费商用还是商业用户，或者至少已经非常接近这样做了。我在

纯C ++中编写代码，我经常不得不在我的

代码中使用它来使它在Visual C ++中工作。


这是一个我的意思的简单例子：


#ifdef _WIN32

模板< typename T，

模板< typename元素，

typename Alloc = std :: allocator< ELEM> >

class Container = std :: deque>

class Stack

{

Container< T，的std ::分配器< T> > m_elems;

#else


模板< typename T，

模板< typename元素，

typename = std :: allocator< ELEM> >

class Container = std :: deque>

class Stack

{

Container< T> m_elems;

#endif


请注意_WIN32代码下我需要如何命名Alloc而不是
而不仅仅是设置第二个类型名称默认情况下，以及

课程，VC ++忽略了我必须的默认值

明确定义元素类型的容器和

分配器类型。这很麻烦。


那么，有没有人知道为什么微软没有聘请

模板专家来正确实施模板？我想b $ b假设他们只是想杀死C ++以及他们发明的一切。呃，好吧。毕竟它将是一个C＃

世界。 Ugggg。


Thomas J. Clancy

解决方案

对不起，代码示例应如下所示


#ifdef _WIN32

模板< typename T，

模板< typename元素，

typename Alloc =的std ::分配器<组件> >

class Container = std :: deque>

class Stack

{

Container< T，的std ::分配器< T> > m_elems;

#else


模板< typename T，

模板< typename元素，

typename = std :: allocator< Element> >

class Container = std :: deque>

class Stack

{

Container< T> m_elems;

#endif

-----原帖-----

我是就是想。经过所有这些年来在Visual C ++上工作
之后，为什么微软还没有看到完全实现C ++标准的模板部分，而其他供应商（包括免费和商业版）都是如此。有，或者至少已经非常接近这样做了。我用纯粹的C ++编写代码，我经常不得不在我的代码中找到它才能使它在Visual C ++中工作。

这是一个简单的例子我的意思是：

#ifdef _WIN32
模板< typename T，
模板< typename元素，
typename Alloc = std :: allocator< ELEM> >
类Container = std :: deque>
类Stack
{
容器< T，std :: allocator< T> > m_elems;
#else

模板< typename T，
模板< typename元素，
typename = std :: allocator< ELEM> >
类Container = std :: deque>
类Stack
{
容器< T> m_elems;
#endif

请注意_WIN32代码下如何命名Alloc
只需设置第二个typename'的默认值，然后选择
在正文中，VC ++忽略了我必须用元素类型和
分配器类型显式定义Container的默认值。这很麻烦。

那么，有没有人知道为什么微软没有聘请
模板专家来正确实施模板？我认为他们只是试图杀死C ++以及他们没有发明的一切。呃，好吧。毕竟它将是一个C＃
世界。 Ugggg。

Thomas J. Clancy
。

Thomas J. Clancy写道：

我只是想知道。经过所有这些年的Visual C ++工作，为什么微软还没有看到完全实现C ++标准的模板部分呢？
许多其他供应商，包括免费和商业，有，或至少已经非常接近这样做。


实际上，只有一家供应商（Comeau）甚至声称完全实现了C ++标准。与早期版本的VC ++相比，VC7.1向前迈出了一大步，未来的版本将更好。

我用纯C ++编写代码为了让它在Visual C ++中工作，我经常不得不从我的代码中解脱出来。


当然你不 - 你选择。在这里给出的例子中，

" MSVC"版本也是100％合法的C ++代码，您的其他编译器可能会接受
。为什么不简单地在任何地方使用该表单，而不是使用#ifdefs使你的代码混乱？

所以，有没有人知道为什么微软没有雇用一个
模板专家正确实现模板？我认为他们只是试图杀死C ++以及他们没有发明的一切。呃，好吧。毕竟它将是一个C＃
世界。 Ugggg。

实际上，微软正投入大量资源来支持和开发C ++。然而，事实是，完全支持

模板非常困难，直到最近，并没有成为客户优先考虑的事情。向后兼容性和代码生成质量对MS的主要客户群来说更为重要。请放心：微软对C ++的承诺是非常强大的。 VC7.1并不完美，但

这是对VC6的巨大改进。


-cd

-----原始消息-----
Thomas J. Clancy写道：

我只是想知道。经过所有这些年在Visual C ++上工作
之后，为什么微软还没有看到适合完全实现C ++标准的模板部分当
这么多其他供应商，包括免费和商业，有，或者
至少已经非常接近这样做。
实际上，只有一个供应商（Comeau）甚至声称

已经完全实现了C ++标准。与早期版本的VC ++相比，VC7.1是一个巨大的步骤
，未来版本将更好地为
。


最新版本的GCC编译大部分标准

模板的东西都没问题，这就是为什么我问

左右VC ++。当我使用

GCC / G ++编写Linux或Unix代码然后将其移植到Windows时，我经常需要使用VC ++ 7.1来ifdef，

。这就是提示这些

问题的原因。

我用纯粹的C ++编写代码我常常有如果只是为了让它在Visual C ++中运行，那么我就可以了解它。

当然你不 - 你选择了。在示例中，您

在这里给出MSVC和MSVC。版本也是100％合法的C ++代码，你的
其他编译器可能会接受。为什么不简单地在任何地方使用该表单，
而不是用#ifdefs来混淆你的代码？


见上面的评论。我经常使用GCC基于标准

编写。移植时我会注意到问题和ifdef。

是的，我可以轻松地降级我的代码以符合VC ++

7.1然后我可以取消ifdef。所以你在这里是正确的，但是，它仍然是一个痛苦的屁股必须

看到关于完全有效和标准的错误信息 -

符合代码。

那么，有没有人知道为什么微软没有聘请
模板专家正确实施模板？我认为他们只是试图杀死C ++以及他们没有发明的一切。呃，好吧。毕竟，这将是一个
C＃世界。 Ugggg。

实际上，微软正投入大量资源来支持和开发C ++，以支持和支持
。然而，问题的事实是，
完全支持模板是非常困难的，直到最近非常b $ b，并不是客户的优先事项。向后兼容性和代码 -
生成质量对于MS的主要客户群来说更为重要。休息
放心：微软对C ++的承诺非常强大。 VC7.1
并不完美，但是它比VC6有了很大的改进。

我同意VC6的巨大改进。是的，

完整的模板支持很难，但我相信这对于没有实现某些东西的有效借口来说，

尤其是微软拥有的资源处理它的价格。


我相信你对客户的优先权是正确的。

大多数人都不喜欢无论如何，我真的很了解模板而且

可能没有太多关于纯标准的要求

在学术领域以外的一致性，但我仍然不会

发现这是一个充分的理由，不开发符合标准的产品

，特别是因为

标准现在已经五年了。


虽然你声称微软致力于C ++，但是我觉得很难相信，特别是

现在使用C＃和他们已添加的所有gastly扩展

C ++。如果他们的标准合规性似乎是支持b $ b b / b。现在我说好像是。您的评估中可能

是正确的。当你没有承诺一个

环境/一个编译器并且必须创建可移植代码时，它只会有点尴尬
令人沮丧

和找出所有

编译器之间的共同点。 :-)


Tom

I was just wondering. After all these years of working on
Visual C++, why hasn''t Microsoft yet seen fit to fully
implement the template portion of the C++ standard when so
many other vendors, both free and commercial, have, or at
least have come very close to doing so. I write code in
pure C++ and I so often have to ifdef the heck out of my
code just to get it to work in Visual C++.

Here is a simple example of what I mean:

#ifdef _WIN32
template<typename T,
template<typename Element,
typename Alloc = std::allocator<ELEM> >
class Container = std::deque >
class Stack
{
Container<T,std::allocator<T> > m_elems;
#else

template<typename T,
template<typename Element,
typename = std::allocator<ELEM> >
class Container = std::deque >
class Stack
{
Container<T> m_elems;
#endif

Note how under the _WIN32 code I need to name Alloc rather
than just setting the second typename''s default, and of
course in the body, VC++ ignores the default an I have to
explicitly define Container with the element type and the
allocator type. This is just messy.

So, does anyone know why Microsoft just hasn''t hired a
template expert to implement templates correctly? I
suppose that they are just trying to kill C++ as well as
everything not invented by them. Ah well. It''ll be a C#
world after all. Ugggg.

Thomas J. Clancy

解决方案

Sorry, the code sample should read as follows

#ifdef _WIN32
template<typename T,
template<typename Element,
typename Alloc = std::allocator<Element> >
class Container = std::deque >
class Stack
{
Container<T,std::allocator<T> > m_elems;
#else

template<typename T,
template<typename Element,
typename = std::allocator<Element> >
class Container = std::deque >
class Stack
{
Container<T> m_elems;
#endif

-----Original Message-----

I was just wondering. After all these years of working onVisual C++, why hasn''t Microsoft yet seen fit to fully
implement the template portion of the C++ standard when somany other vendors, both free and commercial, have, or at
least have come very close to doing so. I write code in
pure C++ and I so often have to ifdef the heck out of my
code just to get it to work in Visual C++.

Here is a simple example of what I mean:

#ifdef _WIN32
template<typename T,
template<typename Element,
typename Alloc = std::allocator<ELEM> >
class Container = std::deque >
class Stack
{
Container<T,std::allocator<T> > m_elems;
#else

template<typename T,
template<typename Element,
typename = std::allocator<ELEM> >
class Container = std::deque >
class Stack
{
Container<T> m_elems;
#endif

Note how under the _WIN32 code I need to name Alloc ratherthan just setting the second typename''s default, and of
course in the body, VC++ ignores the default an I have to
explicitly define Container with the element type and the
allocator type. This is just messy.

So, does anyone know why Microsoft just hasn''t hired a
template expert to implement templates correctly? I
suppose that they are just trying to kill C++ as well as
everything not invented by them. Ah well. It''ll be a C#
world after all. Ugggg.

Thomas J. Clancy
.

Thomas J. Clancy wrote:

I was just wondering. After all these years of working on
Visual C++, why hasn''t Microsoft yet seen fit to fully
implement the template portion of the C++ standard when so
many other vendors, both free and commercial, have, or at
least have come very close to doing so.
Actually, only a single vendor (Comeau) even claims to have fully
implemented the C++ standard. VC7.1 is a huge step forward compared to
earlier versions of VC++, and future version will be better still.
I write code in
pure C++ and I so often have to ifdef the heck out of my
code just to get it to work in Visual C++.
Of course you dont - you choose to. In the example you give here, the
"MSVC" version is also 100% legal C++ code that your other compilers would
likely accept. Why not simply use that form everywhere, rather than
cluttering your code with #ifdefs?
So, does anyone know why Microsoft just hasn''t hired a
template expert to implement templates correctly? I
suppose that they are just trying to kill C++ as well as
everything not invented by them. Ah well. It''ll be a C#
world after all. Ugggg.

Actually, Microsoft is devoting considerable resources to supporting and
developing C++. The fact of the matter is, however, that fully supporting
templates is exremently difficult, and up until very recently, hasn''t been a
customer priority. Backwards compatibility and code-generation quality are
much more important to MS''s main customer base. Rest assured: the
commitment to C++ at Microsoft is very strong. VC7.1 isn''t perfect, but
it''s a huge improvement over VC6.

-cd

-----Original Message-----
Thomas J. Clancy wrote:

I was just wondering. After all these years of working on Visual C++, why hasn''t Microsoft yet seen fit to fully
implement the template portion of the C++ standard when so many other vendors, both free and commercial, have, or at least have come very close to doing so.
Actually, only a single vendor (Comeau) even claims to

have fullyimplemented the C++ standard. VC7.1 is a huge step forward compared toearlier versions of VC++, and future version will be better still.
The latest versions of GCC compile most of the standard
template stuff with little problem, which is why I asked
about VC++. When I write code for Linux or Unix using
GCC/G++ and then port it to windows I often have to ifdef,
even now with VC++ 7.1. This is what prompted these
questions.

I write code in
pure C++ and I so often have to ifdef the heck out of my
code just to get it to work in Visual C++.

Of course you dont - you choose to. In the example you

give here, the"MSVC" version is also 100% legal C++ code that your other compilers wouldlikely accept. Why not simply use that form everywhere, rather thancluttering your code with #ifdefs?

See my above comment. I often write based on the standard
using GCC. When porting I notice the problems and ifdef.
Yes, I could easily downgrade my code to conform to VC++
7.1 and then I could do away with ifdefs. So you are
correct here, but still, its a pain in the butt having to
see error messages regarding completely valid and standard-
conforming code.

So, does anyone know why Microsoft just hasn''t hired a
template expert to implement templates correctly? I
suppose that they are just trying to kill C++ as well as
everything not invented by them. Ah well. It''ll be a C# world after all. Ugggg.

Actually, Microsoft is devoting considerable resources to

supporting anddeveloping C++. The fact of the matter is, however, that fully supportingtemplates is exremently difficult, and up until very recently, hasn''t been acustomer priority. Backwards compatibility and code- generation quality aremuch more important to MS''s main customer base. Rest assured: thecommitment to C++ at Microsoft is very strong. VC7.1 isn''t perfect, butit''s a huge improvement over VC6.

I do agree about the huge improvements over VC6. And yes,
full template support is difficult, but I believe this to
not be a valid excuse for not implementing something,
especially with the resources that microsoft has at its
disposal.

I believe you are correct about the customer priority.
Most people don''t really understand templates anyway and
there probably isn''t much of a call for pure standards
conformance outside the academic realm, but I still don''t
find this an adequate excuse for not developing a product
that conforms to the standard, especially given that the
standard is now five years old.

Although you claim that microsoft is committed to C++, for
some reason I find that difficult to believe, especially
now with C# and all the gastly extensions they''ve added to
C++. If anything their standards compliance seems to be
on the back burner. Now I said "seems to be." You might
be correct in your assessment. It just gets a little
frustrating when you''re not committed to one
environment/one compiler and have to create portable code
and figure out the common denominator between all
compilers. :-)

Tom

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