我正在测试在C / C++程序中嵌入Python,但是我缺乏理解。
测试程序很简单:
我观察到Timer事件是在方法Py_FinalizeEx()的调用期间执行的; ;
所以:
在事件循环期间,C++程序如何与Python程序交互?
python代码:
from threading import *
count = 0;
def foo():
global count
t = Timer(0.1, foo)
t.start()
count= count+1;
print("foo " + str(count), flush=True)
foo()
C++代码
// initialize
Py_InitializeEx(0);
// execute foo.py
PyRun_SimpleStringFlags("exec(open('foo.py'.encode('utf-8')).read())",nullptr);
// wait 5s
qDebug() << "wait 1 begin";
QTime t = QTime::currentTime().addSecs(5);
while(t > QTime::currentTime());
qDebug() << "wait 1 end";
// display value
PyRun_SimpleStringFlags("print(count)",nullptr);
// wait 5s
qDebug() << "wait 2 begin";
t = QTime::currentTime().addSecs(5);
while(t > QTime::currentTime());
qDebug() << "wait 2 end";
qDebug() << "finalize: begin";
Py_FinalizeEx();;
qDebug() << "finalize: end";
结果:
foo 1
wait 1 begin
wait 1 end
wait 2 begin
1
wait 2 end
finalize: begin
foo 2
foo 3
foo 4
foo 5
foo 6
foo 7
foo 8
foo 9
foo 10
最佳答案
伊卡洛斯的解决方案对我有帮助:
Surround your "wait begin" and "wait end" with Py_BEGIN_ALLOW_THREADS and Py_END_ALLOW_THREADS
这些宏对应于以下代码:
// Py_BEGIN_ALLOW_THREADS
{
PyThreadState *save
save = PyEval_SaveThread();
// -------------
qDebug() << "wait 1 begin";
QTime t = QTime::currentTime().addSecs(5);
while(t > QTime::currentTime());
qDebug() << "wait 1 end";
// Py_END_ALLOW_THREADS
PyEval_RestoreThread(save);
}
// --------------
我用Qt事件开发了另一个版本:
from threading import *
count = 0;
def foo():
global count
if count < 20:
t = Timer(1, foo)
t.start()
count= count+1;
print("foo " + str(count), flush=True)
foo()
#ifndef TEST_H
#define TEST_H
#include <QObject>
#include <QTimer>
#undef slots
#include <Python.h>
#define slots
class PythonTest : public QObject
{
Q_OBJECT
PyThreadState *save;
QTimer _timer;
int count = 0;
public:
explicit PythonTest(QObject *parent = nullptr);
signals:
public slots:
void read();
void stop();
};
#endif // TEST_H
#include "pythontest.h"
#include <QDebug>
PythonTest::PythonTest(QObject *parent) : QObject(parent)
{
qDebug() << "start: begin";
Py_InitializeEx(0);
PyRun_SimpleStringFlags("exec(open('foo.py'.encode('utf-8')).read())",nullptr);
_save = PyEval_SaveThread();
_timer.setInterval(5000);
QObject::connect(&_timer, &QTimer::timeout, this, &PythonTest::read);
_timer.start();
qDebug() << "start: end";
}
void PythonTest::read()
{
qDebug() << "read: begin";
if(_count>10)
{
QObject::disconnect(&_timer, &QTimer::timeout, this, &PythonTest::read);
QObject::connect(&_timer, &QTimer::timeout, this, &PythonTest::stop);
}
PyEval_RestoreThread(_save);
PyRun_SimpleStringFlags("print('read ' + str(count),flush=True)");
_save = PyEval_SaveThread();
_count++;
qDebug() << "read: end";
}
void PythonTest::stop()
{
qDebug() << "stop: begin";
QObject::disconnect(&_timer, &QTimer::timeout, this, &PythonTest::stop);
PyEval_RestoreThread(_save);
Py_FinalizeEx();
qDebug() << "stop: end";
}
输出:
start: begin
foo 1
start: end
foo 2
foo 3
foo 4
foo 5
foo 6
read: begin
read: end
read6
foo 7
foo 8
foo 9
foo 10
read: begin
read: end
read10
foo 11
foo 12
foo 13
foo 14
foo 15
read: begin
read: end
read15
foo 16
foo 17
foo 18
foo 19
foo 20
read: begin
read: end
read20
foo 21
read: begin
read: end
read21
read: begin
read: end
read21
read: begin
read: end
read21
...
关于python - 使用python事件并与c++交互,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/59307739/