使用swig创建python模块是最简单的部分。 但是,如果这个模块必须与我的C++应用程序交互,将其从其嵌入式Python实例中导入?p>
例如@flex在如何向应用程序公开python模块方面提供了一个很好的示例:How can I implement a C++ class in Python, to be called by C++?
我想要的是应用程序和模块能够相互交互,比如共享变量和调用回调等等,所以我发现这个答案对于任务来说有点太复杂了。 关于如何实现这一点,我真的找不到太多其他的东西,swig文档也没有解释这一点(我想它更多地与python有关,而不是与swig有关,这就是为什么swig文档中没有提到它的原因)
我发现,我也可以只包括在我C++应用程序中使用SWIG创建的*yWrAP.cxx文件,并获得相同的结果(见下面的代码)
我刚从SWIG和Python开始,这就是为什么我现在的问题是,有没有比我更好的方法或官方方法来实现相同的结果?我忽略了什么吗?
我是否可以在初始化python实例之前导入swig模块,而不必包含Swigtest_wrap.cxx文件?
以下三个文件包含python模块所需的所有内容。只包含一个类,稍后我想将其用作新python类的基类
#ifndef SWIGTEST_H
#define SWIGTEST_H
class Callback
{
public:
Callback(){}
virtual ~Callback() {}
// we want to override this function in python
virtual void Exec() {}
static void callFunc();
static void setCallback(Callback* callback);
private:
static Callback* m_callback;
};
#endif // SWIGTEST_H
Callback* Callback::m_callback = nullptr;
void Callback::callFunc()
{
if(m_callback != nullptr)
{
m_callback->Exec();
return;
}
std::cout << "callback not set" << std::endl;
}
void Callback::setCallback(Callback* callback)
{
m_callback = callback;
}
这里唯一需要注意的是“director”功能的激活
%module(directors="1") mymodule
// We need to include Swigtest.h in the SWIG generated C++ file
%{
#include <iostream>
#include "Swigtest.h"
%}
// Enable cross-language polymorphism in the SWIG wrapper.
%feature("director") Callback;
// Tell swig to wrap everything in Swigtest.h
%include "Swigtest.h"
这个python脚本创建一个从回调类派生的新类,并将回调设置为 这个班
import mymodule
# lets create a new class derived from callback
class MyPyCallbackFromC(mymodule.Callback):
def Exec(self):
print("this class was created in python - It worked!")
callback = mymodule.Callback()
mycallback = MyPyCallbackFromC()
# set callback to this new class
callback.setCallback(mycallback)
# now lets call it from our c++ application
#include <Python.h>
#include <iostream>
#include "Swigtest.h"
// we include this file to be able to append the python
// module table with our own swig wrapped module
#include "Swigtest_wrap.cxx"
int main()
{
// *_wrap.cxx has to be included for PyInit__mymodule;
// must be added before the Python instance is initialized!
PyImport_AppendInittab("_mymodule", PyInit__mymodule);
Py_Initialize();
// create Callback class
Callback* callback = new Callback();
// call Exec() function of linked class
// should return error because no class is set as Callback yet
callback->callFunc();
// execute our script which sets a new class as our callback
FILE* fp;
const char* filename;
filename = "Swigtest.py";
fp = _Py_fopen(filename, "r");
PyRun_SimpleFile(fp, filename);
// if we now call the callback from our application
// the Exec function that was defined in our python script should be executed
callback->callFunc();
delete callback;
Py_Finalize();
}
#swig
swig -c++ -python Swigtest.i
#compile
g++ -fpic -c Swigtest.cpp Swigtest_wrap.cxx -I/pathTo/python
#build
g++ -Wall -Wextra -shared Swigtest.o Swigtest_wrap.o -o _mymodule.so
#compile
g++ -fpic -c Swigtest.cpp
g++ -fpic -c main.cpp -I/pathTo/python
#build
g++ main.o Swigtest.o -o libmyapp.so -I/pathTo/python -lpython3
$ ./libmyapp.so
callback not set
this class was created in python - It worked!
就这样
目前没有回答
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