Qt中进程的相关操作使用QProcess类。

1. 进程间无通信

使用QProcess的execute()方法。

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QProcess process;
QString cmd = "python";
QStringList argvs;
argvs << "run.py" << QString::number(1) << "a" << "b";
int ret = process.execute(cmd, argvs);
if (ret < 0)
{
    qWarning() << "Process execute failed: " << ret << process.error();
}
process.close();

对应的run.py文件为：

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import sys
number_map = {
    "0": ("a", "b", "c"),
    "1": ("a1", "b1", "c1")
}

def download_one(argv1, argv2, argv3): 
    print("argv data", argv1, argv2, argv3)
    [a, b, c] = number_map.get(, ("0", "0", "0"))

def download_last(): 
    while (True):
        [argv1, argv2, argv3] = input("input:").split()
        if argv1 == "exit":
            break
        print("input data", argv1, argv2, argv3)
        [a, b, c] = number_map.get(argv1, ("0", "0", "0"))

if __name__ == '__main__':
    download_one(sys.argv[1], sys.argv[2], sys.argv[3])
    # download_last()

2. 进程间使用标准输入输出

QProcess调用python进程的并实现进程间的读写。使用QProcess的start()方法。
c++代码如下，

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QProcess process;
QString cmd = "python";
QStringList argvs;
argvs << "run.py";
process.start(cmd, argvs);
if (!process.waitForStarted())
{
    qCritical() << "start process failed";
    return;
}
process.waitForReadyRead();
qDebug() << "python to start" << process.readAll();
for (int index = 0; index < 10; index++)
{
    int a = 1;
    QString b = "abc";
    QString c = "c";
    QString params = QString::number(a) + " " + b + " " + c + "\n";
    process.write(params.toStdString().c_str());
    bool ret = process.waitForBytesWritten(); 
    if (!ret)
    {
        qWarning() << "Process execute failed: " << ret << process.error();
    }
    process.waitForReadyRead();
    QByteArray qba = process.readAll();
    qDebug() << "python download log:" << qba;
    // process
    ...
}
}
process.write("exit 0 0");
process.waitForFinished(3000);
process.close();

python, run.py代码如下：

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import sys
number_map = {
    "0": ("a", "b", "c"),
    "1": ("a1", "b1", "c1")
}

def download_last(): 
    while (True):
        [argv1, argv2, argv3] = input("input:").split()
        if argv1 == "exit":
            break
        print("input data", argv1, argv2, argv3)
        [a, b, c] = number_map.get(argv1, ("0", "0", "0"))

if __name__ == '__main__':
    # download_one(sys.argv[1], sys.argv[2], sys.argv[3])
    download_last()

3. 关闭指定的进程

程序运行中有时可以控制其他进程的关闭，比如使用多个QWebEngine，无法正常退出程序，在退出时，手动关闭这些Qtwebengineprocess.exe进程即可：

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void closeProcess(const QString appName)
{
    QString cmd = "taskkill /im " + appName + " /f";
    QProcess pro;
    pro.execute(cmd);
    pro.close();
}

// example
closeProcess("Qtwebengineprocess.exe");

非Qt的c++程序中，可是使用system(“***”)方法实现进程的关闭：

  • windows：system("taskkill /f /t /im app.exe");