I am trying to achieve call Python functions from C++. I thought it could be achieved through function pointers, but it does not seem to be possible. I have been using boost.python to accomplish this.
Say there is a function defined in Python:
def callback(arg1, arg2):
#do something
return something
Now I need to pass this function to C++, so that it can be called from there. How do I write the code on C++ side using boost.python to achieve this?
If it might have any name:
Pass it to a function that takes a boost::python::object.
bp::object pycb; //global variable. could also store it in a map, etc
void register_callback(bp::object cb)
{
pycb = cb;
}
If it is in a single known namespace with a consistent name:
bp::object pycb = bp::scope("namespace").attr("callback");
bp::object has operator() defined, so you call it just like any function
ret = pycb()
Not a clue. But you can use PyObject_Call() to call it once you have the function object.
boost::python::object, you can just use its operator() to call it.I've not used it before, but the reference manual has a section called Calling Python Functions and Methods which seems to show how to do this.
I used PyRun_SimpleString("myFunction()") as quick hack, as my function's name was known, took no args and lived in the __main__ namespace. Note you additionally need to get lock GIL if you are multi-threaded.
