[PyKDE] un-connectable signals (probably sip bug)

[Stefan Bund]

I have analyzed the situation a bit further. I don't know, if I read
the sip source correctly, but as far as I can understand it,

David Boddie <david at boddie.org.uk> writes:
> The following connection attempt
>
>  k.connect(k, SIGNAL("windowAdded(unsigned long)"), fn)
>
> returns False, whereas

in this case, the PyKDE wrapper winds the proxySlot(unsigned long) in
it's table but Qt::connect returns false, since there is no
'windowAdded(unsigned long)' signal.

>  k.connect(k, SIGNAL("windowAdded(long)"), fn)
>  k.connect(k, SIGNAL("windowAdded(ulong)"), fn)
>
> both cause RuntimeError exceptions to be raised.

and in this case, PyKDE raises a RuntimeError since it cannot find a
proxySlot for either 'windowAdded(long)' or 'windowAdded(ulong)'.

As I can read it, the parameter specs are compared as strings ignoring
any whitespace. On the other hand, I have a feeling, that somewhere in
sip's guts, the knowledge, that WId is a typedef for unsigned long
exists, otherwise sip would try to generate proxySlot's for 'unsigned
long' *as well as* 'WId' which would fail, since C++ does not allow
overloading of identical typedef'ed types.

As I understand the situation, for exactly that reason, sip somewhere
filters the list of proxySlot's to generate. This information would
have to be used somewhere in sip/siplib/qtlib.cpp:searchProxySlotTable
to alias 'unsigned long' with 'WId'.

A short-term solution would be, to allow a for a four argument form of
the Connect statement to connect to a python slot along the lines of:

Qt.connect(sender,SIGNAL("windowAdded(WId)"),receiver.pyfunc,SLOT("pyfunc(unsigned long)"))

where receiver.pyfunc is the receiving function and the SLOT argument
just specifies the proxy to use ...

Right now, I had to work around this problem using QTimer and polling
KWinModule.windows() at regular intervals. Pretty scary but it works
;-/

I would be very interested in a long-term fix of this problem.

I have another problem (concerning the inability to really use
QByteArray) but thats another mail.

I will be on Christmas Holiday for the next two weeks and will only
have sporadic Internet access, so I might not answer promptly

Thank you for all the information,

Stefan Bund.

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