qt.network.ssl: No functional TLS backend was found ?

BVladimir

Thanks.
But is openssl really necessary for the simplest qml window?

BVladimir

Does not work - version 1.1.1L- copied the content...\OpenSSL-Win64\lib to ...\x64\Debug where is my dll - nothing...

raven-worx

@BVladimir said in qt.network.ssl: No functional TLS backend was found ?:

But is openssl really necessary for the simplest qml window?

no, but it seems you are loading resources from secured network address (main_window.qml: Network error)

@BVladimir said in qt.network.ssl: No functional TLS backend was found ?:

Does not work - version 1.1.1L- copied the content...\OpenSSL-Win64\lib to ...\x64\Debug where is my dll - nothing...

as i said make sure they are in the PATH env variable or next to your executable.

BVladimir

I don't have an exe file, just a python script calling a function from a dll. The entire openssl lib is in the directory with the dll. In the dll itself, the only code from qt:

int argc = 1;
const char* p1{ "C" };
const char** argv = &p1;
QGuiApplication app(argc, (char**) argv);

QCoreApplication::addLibraryPath("C:\Program Files\OpenSSL-Win64\lib");
QQmlApplicationEngine engine;
const QUrl url(QStringLiteral("C:\C++\for_quik_lua535\x64\Debug\main_window.qml"));
QObject::connect(&engine, &QQmlApplicationEngine::objectCreated, &app,
[url](QObject* obj, const QUrl& objUrl) { if (!obj && url == objUrl) QCoreApplication::exit(-1);},
Qt::QueuedConnection);
engine.load(url);
return PyLong_FromLong(app.exec());

SGaist

Hi,

That's not the purpose of addLibraryPath. As @raven-worx already suggested the .dlls should be findable in the PATH environment variable.

How are you starting your script ?

How did you install Python ?

Can you explain what your script does ?

BVladimir

addLibraryPath - just in case. env. path is set.
py script, starting from VS 2019, python 3.9 by standard installer:

from importlib.machinery import ExtensionFileLoader
dll = ExtensionFileLoader('py2quik_module', r'C:\C++\for_quik_lua535\x64\Debug\for_quik_lua535.dll').load_module()

if name == 'main':
py_obj = dll.py2dll_obj(None)

SGaist

@BVladimir said in qt.network.ssl: No functional TLS backend was found ?:

py2quik

Would you mind explaining what exactly you are trying to load ?

BVladimir

My dll "for_quik_lua535.dll" is a Python/C extension named "py2quik_module" in python

SGaist

Out of curiosity, why not use PySide or PyQt since you are already working with Python ?

BVladimir

I think it will work faster in c++ - a lot of online data is planned. Python for the general scenario.

SGaist

What kind of data do you intend to process ?

BVladimir

Data from stock exchange terminal

BVladimir

I tried to build an exe file:

#include <QGuiApplication>
#include <QQmlApplicationEngine>

int main(int argc, char* argv[]) {
int argc2 = 1;
const char* p1{ "C" };
const char** argv2 = &p1;

QGuiApplication app(argc2, (char**)argv2);

QQmlApplicationEngine engine;
const QUrl url(QStringLiteral("qrc:tmpQML/tmpQML.qml"));
QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,
    &app, [url](QObject* obj, const QUrl& objUrl) {
        if (!obj && url == objUrl)
            QCoreApplication::exit(-1);
    }, Qt::QueuedConnection);
engine.load(url);

return app.exec();

}

Same QML:

import QtQuick 2.12
import QtQuick.Controls 2.12

ApplicationWindow {

title: "Qt Quick Controls Gallery"
visible: true
width: 640
height: 480

}

When running from VS 2019, it works fine. And does not try to search any of:

QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/6.2.1/msvc2019_64/plugins/platforms/networkaccess" ...

or

QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/6.2.1/msvc2019_64/plugins/platforms/tls" ...

It's only with dll problem...

SGaist

What are going to use to process your data ?

BVladimir

The main idea is Python calls dll's that receive data and display using qt, General work with data where speed is not needed in Python

SGaist

Well, I must say I fail to understand your architecture here.

What is so speed critical in your app that you need to have your UI in C++ while doing some processing in Python while the rest is done in C++ again.

BVladimir

Data from stock exchange terminal - through с++ & qt, analysis in Python.

SGaist

Why not load the data directly in Python using something like numpy ?

BVladimir

It is assumed that there can be over 10,000 changing values on the screen once per second. I would like to have fewer lags.

SGaist

If you do all the heavy lifting in Python you should benchmark the GUI as well.