您认为此代码会产生任何未定义的行为吗？ [英] Do you think this code will produce any undefined behavior?
问题描述
我正在使用C ++进行高速期货实现，并且正在修改函数指针逻辑的方法。我是一个没有大量使用C ++的/ b $ b C /汇编程序员。所以我的技能
肯定会得到改善。我想知道我是否正在对我的第一个
尝试处理任何未定义行为的函数指针。这是
代码：
http://appcore.home.comcast.net/vzoo...cope-guard.cpp
我基本上使用的是Andrei和Petru范围保护技术，用一个小的
调整：我正在使用一个指向模板化调用细节的函数指针，而不是一个布尔值的
。这样我可以像对范围保护一样使用它来测试函数指针对NULL的值
，我可以把它称为虚拟的
函数。因此，我可以虚拟地或通过
模板化的SafeWxecute函数在本地调用它...这听起来像是C ++大师吗？'
; ^）
谢谢大家的时间，
Chris Thomasson
* Chris Thomasson：
我正在研究C ++中的高速期货实现，并且是
修补周围有包装函数指针逻辑的方法。我是一个没有大量使用C ++的/ b $ b C /汇编程序员。所以我的技能
肯定会得到改善。我想知道我是否正在对我的第一个
尝试处理任何未定义行为的函数指针。这是
代码：
http://appcore.home.comcast.net/vzoo...cope-guard.cpp
我基本上都在使用Andrei和Petru scopeguard技术，有一个小的
调整：我使用一个指向模板化调用细节的函数指针，而不是一个布尔值的
。这样我可以像对范围保护一样使用它来测试函数指针对NULL的值
，我可以把它称为虚拟的
函数。因此，我可以虚拟地或通过
模板化的SafeWxecute函数在本地调用它...这听起来像是C ++大师吗？'
; ^）
否。范围保护员的工作是清理。执行清理行动
不止一次必然会导致问题。如果你想要一个委托，
a可调用实体包装一个对象指针加上成员函数
指针，请考虑标准库和Boost / TR1类。
Boost课程是优越的，因为它们建立在标准库的经验之上，加上1998年以后开发的其他技术。
-
答：因为它弄乱了人们通常阅读文字的顺序。
问：为什么这么糟糕？
A：热门发布。
问：usenet和电子邮件中最烦人的事情是什么？
" Alf P 。斯坦巴赫 < al *** @ start.nowrote in message
news：4s ************ @ mid.individual.net ...
> * Chris Thomasson：
>我正在研究C ++中的高速期货实现，
[...]
>我是想知道我是否第一次尝试使用函数指向任何未定义的行为。这是代码：
http://appcore.home.comcast.net/vzoo...cope-guard.cpp
我基本上使用的是Andrei和Petru范围保护技术，其中一个小
tweak：
[...]
>所以，我可以虚拟地或通过模板化的SafeWxecute
函数在本地调用它...这听起来像是C ++大师吗？'
; ^）
否。范围保护员的工作是清理。
好吧......我认为我用于该对象的名称并不能完全匹配它的
功能。因此，我将整个对象重命名为：
''funcall_base''，它不会在析构函数中调用任何东西;它在其功能的任何方面都不会使用它的范围...
执行清理行动不止一次必然会导致问题。
然后我可以添加一个名为''funcall_scoped''的变体，它确实会在析构函数中调用
，只要它是以前没有被解雇。那个
应该比以前更清楚地定义我的缩进用法...
如果你想要一个委托 ，一个包装对象指针的可调用实体
加上成员函数指针，
这就是我所追求的，除了我有点想在''funcall_base'中远离
虚拟析构函数/函数，因为它最终必须是一个与我的低级兼容的POD
C /汇编库，其中
包含我的新期货算法的实际实现细节。它应该有一个成员，它是一个类型的函数指针，它是一个类型的函数指针。
" standard"到我的低级库：
class funcall_base {
typedef void（* fpfuturesapi_t）（void const *）;
fpfuturesapi_t m_fpcall_virtual;
};
因此库可以直接调用它来获取实际模板化的实现细节以调用自身。另外，我想我可以跳过调用
到''funcall_base''中包含的函数指针：
class funcall_base {
public：
void execute_virtual（）{
m_fpcall_virtual（this）;
}
};
当调用者知道其模板化呼叫详细信息的类型时，
提前：
class funcall_base {
public：
template< typename T_calldetail>
void execute_proxy（）{
static_cast< T_calldetail *>（this） - > ; execute_direct（）;
}
};
//假设mycall是calldetails_t的基类
funcall_base mycall;
//我认为这个电话：
mycall.execute_virtual（）;
//应该有比这次电话更多的开销：
mycall.execute_proxy< calldetails_t>（）;
//我离开这里的路吗？
：^）
我很感激如果你能澄清一下......
考虑标准库和Boost / TR1类。 Boost
课程是优越的，因为他们建立在
标准库的经验基础上，加上1998年以后开发的其他技术。
不幸的是，在我的C ++期货的实现细节中，我无法使用Boost的任何部分或任何其他的b
第三方库
图书馆。
; ^（...
感谢您的耐心等待！
Chris Thomasson写道：
不幸的是，我不能使用Boost的任何部分或其他任何部分
第三方库，在我的C ++期货的实现细节中
库。
; ^（...
为什么不呢？你知道提升是开源的，但不是GPL，对吗？这更像是BSD许可证的b $ b在开源或商业中使用它，无论你想要什么
。
Tony
I am working on a high-speed futures implementation in C++, and was
tinkering around with ways to wrap the function pointer logic. I am a
C/Assembly programmer that doesn''t make a lot of use of C++. So my skills
can be improved upon for sure. I was wondering if I was subjecting my first
attempt at a function pointer to any undefined behavior(s). Here is the
code:
http://appcore.home.comcast.net/vzoo...cope-guard.cpp
I''m basically using Andrei and Petru scopeguard technique, with one small
tweak: I am using a function pointer to the templated call details, instead
of a boolean. That way I can use it like a scopeguard by testing the value
of the function pointer against NULL, and I can call it like a virtual
function of sorts. So, I can call it virtually, or locally through the
templated SafeWxecute function... Does this sound Kosher to you C++ gurus''?
;^)
Thank you all for your time,
Chris Thomasson
* Chris Thomasson:I am working on a high-speed futures implementation in C++, and was
tinkering around with ways to wrap the function pointer logic. I am a
C/Assembly programmer that doesn''t make a lot of use of C++. So my skills
can be improved upon for sure. I was wondering if I was subjecting my first
attempt at a function pointer to any undefined behavior(s). Here is the
code:
http://appcore.home.comcast.net/vzoo...cope-guard.cpp
I''m basically using Andrei and Petru scopeguard technique, with one small
tweak: I am using a function pointer to the templated call details, instead
of a boolean. That way I can use it like a scopeguard by testing the value
of the function pointer against NULL, and I can call it like a virtual
function of sorts. So, I can call it virtually, or locally through the
templated SafeWxecute function... Does this sound Kosher to you C++ gurus''?
;^)No. A scopeguard''s job is to clean up. Executing the clean-up action
more than once is bound to lead to problems. If you want a "delegate",
a callable entity that wraps an object pointer plus member function
pointer, consider the standard library and Boost/TR1 classes for that.
The Boost classes are superior because they build on the experience with
the standard library, plus additional techniques developed after 1998.
--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?
"Alf P. Steinbach" <al***@start.nowrote in message
news:4s************@mid.individual.net...>* Chris Thomasson:>I am working on a high-speed futures implementation in C++,
[...]
>I was wondering if I was subjecting my first attempt at a function
pointer to any undefined behavior(s). Here is the code:
http://appcore.home.comcast.net/vzoo...cope-guard.cpp
I''m basically using Andrei and Petru scopeguard technique, with one small
tweak:
[...]
>So, I can call it virtually, or locally through the templated SafeWxecute
function... Does this sound Kosher to you C++ gurus''?
;^)
No. A scopeguard''s job is to clean up.Okay... I think the name I used for the object didn''t safely match its
functionality. Therefore, I will rename the entire object to something like:
''funcall_base'' which will not call anything in the destructor; it won''t use
its scope in any aspect of its functionality...
Executing the clean-up action more than once is bound to lead to problems.Then I can add a variant called ''funcall_scoped'' which will indeed invoke
the call in its destructor, only if it was not previously "Dismissed". That
should define my indented usage a bit clearer than before...
If you want a "delegate", a callable entity that wraps an object pointer
plus member function pointer,That''s kind of what I am after, except I kind of want to stay away from
virtual destructors/functions in ''funcall_base'' because it ultimately has to
be a POD that is compatible with my low-level C/Assembly library, which
contains the actual implementation details of my new futures algorithm. It
should have a single member which is a function pointer of a type that is
"standard" to my low-level library:
class funcall_base {
typedef void (*fpfuturesapi_t) (void const*);
fpfuturesapi_t m_fpcall_virtual;
};
So that the library can call it directly to get the actual templated
implementation details to invoke itself. Also, I think I can skip calls
into the function pointer contained in ''funcall_base'':
class funcall_base {
public:
void execute_virtual() {
m_fpcall_virtual(this);
}
};
when the type of its templated call details are known by the caller in
advance:
class funcall_base {
public:
template<typename T_calldetail>
void execute_proxy() {
static_cast<T_calldetail*>(this)->execute_direct();
}
};
// assume mycall is base class of calldetails_t
funcall_base mycall;
// I think that this call:
mycall.execute_virtual();
// should have more overhead than this call:
mycall.execute_proxy<calldetails_t>();
// Am I way off base here?
:^)
I would appreciate it if you could clarify a bit...
consider the standard library and Boost/TR1 classes for that. The Boost
classes are superior because they build on the experience with the
standard library, plus additional techniques developed after 1998.Unfortunately, I can''t make use of any part of Boost, or any other
third-party library, in the implementation details of my C++ futures
library.
;^(...
Thanks for your patience!
Chris Thomasson wrote:
Unfortunately, I can''t make use of any part of Boost, or any other
third-party library, in the implementation details of my C++ futures
library.
;^(...
Why not? You know that boost is open source but NOT GPL, right? It is
more like BSD license - use it in open source or commercial, whatever
you want.
Tony
这篇关于您认为此代码会产生任何未定义的行为吗？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
