[英]SWIG passing argument to python callback function
So I'm almost done. 所以我差不多完成了。 Now I have working code which calls python callback function.
现在我有工作代码调用python回调函数。
Only thing I need now is how to pass argument to the python callback function. 我现在唯一需要的是如何将参数传递给python回调函数。
My callback.c is: 我的callback.c是:
#include <stdio.h>
typedef void (*CALLBACK)(void);
CALLBACK my_callback = 0;
void set_callback(CALLBACK c);
void test(void);
void set_callback(CALLBACK c) {
my_callback = c;
}
void test(void) {
printf("Testing the callback function\n");
if (my_callback) (*my_callback)();
else printf("No callback registered\n");
}
My callback.i is: 我的callback.i是:
// An entirely different mechanism for handling a callback
%module callback
%{
typedef void (*CALLBACK)(void);
extern CALLBACK my_callback;
extern void set_callback(CALLBACK c);
extern void my_set_callback(PyObject *PyFunc);
extern void test(void);
%}
extern CALLBACK my_callback;
extern void set_callback(CALLBACK c);
extern void my_set_callback(PyObject *PyFunc);
extern void test(void);
%{
static PyObject *my_pycallback = NULL;
static void PythonCallBack(void)
{
PyObject *func, *arglist;
PyObject *result;
func = my_pycallback; /* This is the function .... */
arglist = Py_BuildValue("()"); /* No arguments needed */
result = PyEval_CallObject(func, arglist);
Py_DECREF(arglist);
Py_XDECREF(result);
return /*void*/;
}
void my_set_callback(PyObject *PyFunc)
{
Py_XDECREF(my_pycallback); /* Dispose of previous callback */
Py_XINCREF(PyFunc); /* Add a reference to new callback */
my_pycallback = PyFunc; /* Remember new callback */
set_callback(PythonCallBack);
}
%}
%typemap(python, in) PyObject *PyFunc {
if (!PyCallable_Check($input)) {
PyErr_SetString(PyExc_TypeError, "Need a callable object!");
return NULL;
}
$1 = $input;
}
It works well. 它运作良好。 What should I do so I can pass argument to
my_callback
? 我应该怎么做才能将参数传递给
my_callback
? Any help will be greatly appreciated! 任何帮助将不胜感激!
The arguments to the callback are the second argument to PyEval_CallObject()
. 回调的参数是
PyEval_CallObject()
的第二个参数。 Right now you're building an empty tuple, which means "no arguments". 现在你正在构建一个空元组,这意味着“没有参数”。 So, change that.
所以,改变这一点。 Where you now do:
你现在在哪里:
arglist = Py_BuildValue("()"); /* No arguments needed */
you instead pass Py_BuildValue
whatever arguments you want the Python function to receive. 你改为传递
Py_BuildValue
你希望Python函数接收的参数。 For example, if you want to pass the callback an integer, a string and a Python object you got from somewhere, you would do: 例如,如果要将回调传递给整数,字符串和从某处获得的Python对象,您可以:
arglist = Py_BuildValue("(isO)", the_int, the_str, the_pyobject);
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