[PyQt] Advices on embedding python in Qt/C++ application

[Alexis Barbot]

I looked at it, but it seems I didn't catch the point (or possibly the
moment I read it I did not figure out it could be what I needed...). I now
understand that it explains I should get the c api dynamically to call it,
whereas I was trying to call static method. I could get something roughtly
working this way, with pyqt compiled in static (see code below). I'm
currently trying to clean everythind, but I realized I had to upgrade Qt
for that, as I can't find a PyQt package for Qt5.9 (sad, as it's a LTS). So
I'll keep you updated on my progress.
In my tests I realized something: is there some special care to do with
containers while passing from C++/python? In my first attemp to pass a
QVariantMap the items added after SetItem to python are not visible from
python? (and items modified in python are not modified in c++). Any special
thoughts about this?
Thanks for all your help

Alexis

```
Py_Initialize();
PyEval_InitThreads();
auto sipModule = PyImport_ImportModule("sip");
PyImport_ImportModule("PyQt5.sip");
auto sipAPI = (const sipAPIDef*)PyCapsule_Import("sip._C_API", 0);
PyCapsule_Import("PyQt5.QtCore._C_API", 0);
auto sipModuleDict = PyModule_GetDict(sipModule);
auto sip_sipmod = PyImport_ImportModule("PyQt5.sip");
auto sip_capiobj = PyDict_GetItemString(PyModule_GetDict(sip_sipmod),
"_C_API");

sipAPI_QtCore = reinterpret_cast<const
sipAPIDef*>(PyCapsule_GetPointer(sip_capiobj, "PyQt5.sip._C_API"));
qpycore_init();
sipExportModule(&sipModuleAPI_QtCore, SIP_API_MAJOR_NR, SIP_API,MINOR_NR,
0);

auto m = PyImport_AddModule("__main__");
auto g = PyModule_GetDict(m);
auto d = PyDictNew();

auto test = std::make_unique<QDateTIme>(QDateTIme::currentDateTime);
auto type = sipAPI_QtCore->api_find_type("QDateTime);
auto pyTest = sipAPI_QtCore->api_convert_from_type(test.get(), type,
nullptr);
// Ici je visualise l'objet C++ en python
PyDict_SetItem(d, PyUnicode_FromString("testdate"), Py_file_input, g, d);
PyRun_String("print(testdate.toString())", Py_file_input, g, d);
test->setDate(QDate{2000,02,03});
// Ici je visualise en python que l'objet a été modifié en c++
PyDict_SetItem(d, PyUnicode_FromString("testdate"), Py_file_input, g, d);
Py_FinalizeEx();
```

Le mar. 27 août 2019 à 11:48, Phil Thompson <phil at riverbankcomputing.com> a
écrit :

> Have you read this...
>
> https://www.riverbankcomputing.com/static/Docs/sip/embedding.html
>
> On 27/08/2019 09:45, Alexis Barbot wrote:
> > What do you mean? Should I import this module in the python context? I
> > tried adding this line wihtout any effect:
> > `PyRun_SimpleString("import PyQt5.QtCore")`
> >
> > If we're speaking about some cpp header to include, I can't see which
> > one
> > it is.
> > Thanks
> >
> > Le mar. 27 août 2019 à 10:25, Phil Thompson
> > <phil at riverbankcomputing.com> a
> > écrit :
> >
> >> On 27/08/2019 08:29, Alexis Barbot wrote:
> >> > Thanks for these replies,
> >> >
> >> > First of all, I had a look at PythonQt which indeed looked promising
> in
> >> > my
> >> > case. However I had toubles to build it, so I skipped that solution.
> >> > Now I
> >> > understand that this was probably caused by the compilation attempt
> >> > with
> >> > mingw while using a binary python installer, obviously compiled using
> >> > msvc.
> >> > Furthermore, I got some success with PyQt: after preparing all paths
> >> > and
> >> > adding several flags to the configure command, I could perform the
> >> > complete
> >> > build wihtout errors. I so tried to write a small piece of code to
> >> > validate
> >> > my usage. It builds correctly, but it suddenly stop while running
> >> > without
> >> > any error message. Here is the code:
> >> >
> >> > ```
> >> > #include <QDebug>
> >> > #include <Python.h>
> >> > #include <QDateTime>
> >> > #include <sipAPIQtCore.h>
> >> > #include <memory>
> >> >
> >> > int main(int argc, char* argv[])
> >> > {
> >> >     qDebug() << "start";
> >> >     Py_Initialize();
> >> >     auto d = PyDict_New();
> >> >     auto test = std::make_unique<QDateTime>();
> >> >     auto pyTest = sipConvertFromType(test.get(), sipType_QDateTime,
> >> > nullptr);
> >> >     qDebug() << "end";
> >> >     Py_FinalizeEx();
> >> >     return 0;
> >> > }
> >> > ```
> >> >
> >> > It sounds like everything is installed but I'm missing some
> >> > initialization
> >> > step. Is that possible? Or maybe there's something else I should
> >> > check/try?
> >> > Many thanks for your help.
> >>
> >> You haven't imported PyQt5.QtCore.
> >>
> >> Phil
> >>
> >
> > _______________________________________________
> > PyQt mailing list    PyQt at riverbankcomputing.com
> > https://www.riverbankcomputing.com/mailman/listinfo/pyqt
>
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