linkage

C linkage function cannot return C++ class - error resulting from the contents of my method

由 你说的曾经没有我的故事 提交于 2021-02-19 02:23:42
问题 I am exporting a method that can be called from unmanaged code, but the function itself lives in a managed c++ project. The following code results in a compiler error: error C2526: 'System::Collections::Generic::IEnumerator<T>::Current::get' : C linkage function cannot return C++ class 'System::Collections::Generic::KeyValuePair<TKey,TValue>' error C2526: 'System::Collections::Generic::Dictionary<TKey,TValue>::KeyCollection::GetEnumerator' : C linkage function cannot return C++ class 'System:

C linkage function cannot return C++ class - error resulting from the contents of my method

由 ≡放荡痞女 提交于 2021-02-19 02:23:21
问题 I am exporting a method that can be called from unmanaged code, but the function itself lives in a managed c++ project. The following code results in a compiler error: error C2526: 'System::Collections::Generic::IEnumerator<T>::Current::get' : C linkage function cannot return C++ class 'System::Collections::Generic::KeyValuePair<TKey,TValue>' error C2526: 'System::Collections::Generic::Dictionary<TKey,TValue>::KeyCollection::GetEnumerator' : C linkage function cannot return C++ class 'System:

What does it mean that linkage of main() is implementation defined?

由 我与影子孤独终老i 提交于 2021-02-07 09:49:03
问题 C++ standard section 3.6.1/3 says that The linkage of main is implementation-defined What does it mean? Why it is implementation defined? Is it same in C also? 回答1: The purpose of C++ is to provide a portable abstraction over programming. Many things are specified by the standard so as to be unambiguous regardless of whether you translate your C++ to assembly, JavaScript, cheese, frying pans or supermodels. The linkage of main is not one of those things, because it is a bit of an abstraction

What is the difference between scope and linkage?

由 白昼怎懂夜的黑 提交于 2021-01-27 05:23:04
问题 I tried different websites but I don't get it. Could you explain it in simple english? 回答1: "scope" is a namespace of the compiler; "linkage" is about compiled units. I explain a bit more: A variable declared in a function has the scope of that function, i.e. it is visible only within that function. A variable declared as static in a source file, can be seen only by the code in that source file (and all included files!). Variables can also have global scope: they can be referred to in a

What is the difference between scope and linkage?

由 て烟熏妆下的殇ゞ 提交于 2021-01-27 05:22:31
问题 I tried different websites but I don't get it. Could you explain it in simple english? 回答1: "scope" is a namespace of the compiler; "linkage" is about compiled units. I explain a bit more: A variable declared in a function has the scope of that function, i.e. it is visible only within that function. A variable declared as static in a source file, can be seen only by the code in that source file (and all included files!). Variables can also have global scope: they can be referred to in a

使用树状图做层次聚类分析

由 空扰寡人 提交于 2021-01-05 14:02:56
一、实验目的 如果您以前从未使用过树状图，那么使用树状图是查看多维数据如何聚集在一起的好方法。 在这本笔记本中，我将简单探索通过层次分析，借助树状图将其可视化。 二、层次分析 层次分析是聚类分析的一种，scipy有这方面的封装包。 linkage函数从字面意思是链接，层次分析就是不断链接的过程，最终从n条数据，经过不断链接，最终聚合成一类，算法就此停止。 dendrogram是用来绘制树形图的函数。 三、实验数据 grain_variety是标签，其他列为多种属性的值（特征）。 from scipy . cluster . hierarchy import linkage , dendrogram import matplotlib . pyplot as plt import pandas as pd seeds_df = pd . read_csv ( 'seeds-less-rows.csv' ) seeds_df . head () #移除grain_variety varieties = list ( seeds_df . pop ( 'grain_variety' )) varieties ['Kama wheat', 'Kama wheat', 'Kama wheat', 'Rosa wheat', 'Rosa wheat', 'Rosa wheat', 'Rosa

使用树状图做层次聚类分析

由 ￡可爱￡侵袭症＋ 提交于 2021-01-05 13:27:26
一、实验目的 如果您以前从未使用过树状图，那么使用树状图是查看多维数据如何聚集在一起的好方法。 在这本笔记本中，我将简单探索通过层次分析，借助树状图将其可视化。 二、层次分析 层次分析是聚类分析的一种，scipy有这方面的封装包。 linkage函数从字面意思是链接，层次分析就是不断链接的过程，最终从n条数据，经过不断链接，最终聚合成一类，算法就此停止。 dendrogram是用来绘制树形图的函数。 三、实验数据 grain_variety是标签，其他列为多种属性的值（特征）。 from scipy.cluster.hierarchy import linkage, dendrogram import matplotlib.pyplot as plt import pandas as pd seeds_df = pd.read_csv('seeds-less-rows.csv') seeds_df.head() #移除grain_variety varieties = list(seeds_df.pop('grain_variety')) varieties ['Kama wheat', 'Kama wheat', 'Kama wheat', 'Rosa wheat', 'Rosa wheat', 'Rosa wheat', 'Rosa wheat', 'Rosa wheat',

C++ 多文件编译简述：头文件、链接性、声明与定义

由 假装没事ソ 提交于 2020-12-26 05:47:12
[TOC] Commen Sense C++ 在编译时对每个翻译单元（Translation Unit，通常是文件，下文以文件代称）单独编译。 注意区分 声明（Declaration） 和 定义（Definition） ： 声明 规定了变量的类型和名字； 定义 则负责创建与名字关联的实体，定义还申请存储空间。[1] C++ 的“单定义规则”指出变量只能有一次定义。 注意区分 作用域（Scope） 和 链接性（Linkage） ： 作用域 描述名称在文件的多大范围可见； 链接性 描述名称如何在不同单元间共享。 头文件 头文件中常包含的内容 函数原型 使用 #define 或 const 定义的符号常量 结构声明 类声明 模板声明 内联函数 普通函数的定义不能放在头文件中，即使使用了 #ifndef 等预处理指令防止头文件被重复包含。这是因为每个源文件被单独编译，头文件中的函数定义会使链接后的程序包含多个重复定义，预处理指令只能保证单个文件被单独编译时不会出现头文件的重复展开。 内联函数需要在每一个调用点都对编译器可见，因此通常直接放在头文件中被所有实现文件 include。 模板函数和模板类的定义不会产生任何“实体”函数，因此可以出现在头文件中。又由于与内联函数类似的原因，其通常都被放在头文件中。 类的声明和实现通常分处于一个头文件（ .h ）和实现文件（ .cpp ）中
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