Question

v8capi.h

typedef struct V8Context V8Context;

#ifdef __cplusplus
extern "C" {
#endif

V8Context *V8_NewContext();

#ifdef __cplusplus
}
#endif

v8capi.cpp

#include <v8.h>

struct V8Context : public v8::Handle<v8::Context> { };

V8Context *V8_NewContext() {
    v8::HandleScope hscope;
    return new V8Context(v8::Context::New());
}

From what I understand, new V8Context(...) should call v8::Handle<T> s constructor which takes a Handle<T>. v8::Context::New() returns a v8::Persistent<T>, which inherits v8::Handle<T>, so that should work. But in reality, it s trying to call a constructor that takes a const V8Context &:

error C2664:  V8Context::V8Context  : cannot convert parameter 1 from
 v8::Persistent<T>  to  const V8Context & 
    with
    [
        T=v8::Context
    ]
    No user-defined-conversion operator available that can perform this
    conversion, or the operator cannot be called

我做了什么错误?

Answer 1

There is no constructor defined in V8Context, so only the implicit copy constructor appears as an option. You need to explicitly define a constructor in V8Context that forwards the v8::Persistent<T> argument to its base class.

Answer 2

在C++中继承了建筑商(尽管在C++11中有一些穿过功能),因此,你不得不在上写你的自己的建筑商,该编码明确称为适当的基类建筑商。

Answer 3

根据我的理解,new V8Context (...)v8:Handle<T> s Constructionor.

<代码>new V8Context(......)将仅指在V8Context/code>上宣布的建筑商;建筑商不继承。你们需要增加一个,例如:



V8Context(v8::Handle<v8::Context> const & handle) : 
    v8::Handle<v8::Context>(handle) 
{}

Answer 4

<代码>new V8Context(...).n t calls a Constructionor from v8:Handle<T>, but a Constructionor from V8Context。由于你对其中的字塔作了界定,只有违约的建筑商和复印件建筑商才能使用(建筑商是可继承的)。因此,它试图打上影印机,并且由于这一论点可能变成了<编码>V8Context。为了解决你的问题,你需要增加一个适当的构造者,以<代码>V8Context,该编码将把论点提交基建商(根据你的论点,并非确切的编号,而是类似的话):

struct V8Context : public v8::Handle<v8::Context> {
  V8Context(const v8::Handle<v8::Context>& handle): v8::Handle<v8::Context>(handle) {}
};

Answer 5

www.un.org/Depts/DGACM/index_french.htm

the copy constructor which is synthesized whenever it is needed and not explicitly declared or made impossible (e.g. by deriving from a class without a copy constructor). This constructor take a V8Cintext as argument.
the default constructor which is synthesized when needed, when there is no explicit constructor, and all members and bases can be default constructed. Thos constructor has no arguments.

看来,你试图通过与复制商签名相对应的那类。如果你想要使用,就需要明确提供相应的建筑。

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