[PyQt] Obtaining a pointer to sqlite3 handle in PyQt5's binding of QtSqlDriver - a QVariant problem

[J Barchan]

@Andrej Radovic
I believe you are the poster at Qt forum a few days ago whom I told to join
up here to pyqt mailing list and ask your question?
I thought it looked like you would need expert PyQt help for it.
As you can see, you get support straight from the horse's mouth here :)

On Sat, 12 Oct 2019 at 12:08, Andrej Radovic <r.andrej at gmail.com> wrote:

> Absolutely. Thank you!
>
> On Sat, 12 Oct 2019, 10:51 Phil Thompson, <phil at riverbankcomputing.com>
> wrote:
>
>> On 11/10/2019 15:23, Andrej Radovic wrote:
>> > Hello everyone, it's my first post here, I'll get straight to the
>> > point.
>> >
>> > I'm trying to register some functions in sqlite within my PyQt5 app. To
>> > do
>> > so
>> > within Python, I'm trying to obtain the pointer (actually, `sqlite3
>> > **`) to
>> > the
>> > sqlite instance, so I could use sqlite3_create_function
>> > (https://sqlite.org/c3ref/create_function.html) through Python's
>> > `ctypes` (https://docs.python.org/3/library/ctypes.html) and register
>> > my
>> > function.
>> >
>> > When doing this in Qt5 instead of Python, you just use
>> > `QSqlDriver::handle()`
>> > (https://doc.qt.io/qt-5/qsqldriver.html#handle), which returns a
>> > QVariant
>> > containing the address. You cast the `QVariant.data()` appropriately
>> > and off
>> > you go. When I try to obtain the handle in Python , I get:
>> >
>> >     db.driver().handle()
>> >     TypeError: unable to convert a C++ 'sqlite3*' instance to a Python
>> > object
>> >
>> > I found that this error is generated within the C++ part of qpycore
>> > (qpy/QtCore/qpycore_chimera.cpp:1539).
>> > The code shows that a QVariant containing a pointer to an unknown type
>> > cannot
>> > be translated to a Python object. However, I don't need a Python
>> > object,
>> > just a
>> > pointer I can use with ctypes.
>> >
>> > Does anyone know of a way to do this? Thanks!
>>
>> In tonight's snapshot it will be converted to a voidptr object...
>>
>>
>> https://www.riverbankcomputing.com/static/Docs/PyQt5/api/sip/sip-module.html#voidptr
>>
>> Is that enough?
>>
>> Phil
>>
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-- 
Kindest,
Jonathan
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