PyQt4 provides a signal and slot system for events and callbacks. This extension provides the pyqt4 domain, which extends the standard python domain with the new pyqt4:signal directive:
Though the pyqt4 domain is derived from the Python domain and can thus work as drop-in replacement for it, you should not use this directive as default domain, unless your complete API only consists for Qt4 types.
As the term “signal” is rather common, other domains may add a directive of this name to the python domain, too. Therefore, it is strongly advisable to document signals by using the fully qualified name of the directive. This clearly marks the signal as PyQt4 signal, avoiding and disambiguities.