ho un errore del genere:
file1.h:705: warning: 'virtual nsresult AAA::funzione(void**)' was hidden
file2.h:212: warning: by 'virtual nsresult BBB::funzione(PRUint32*)'
file.cpp: In member function 'virtual nsresult CCC::metodo(AAA*&)':
file.cpp:189: error: cannot allocate an object of abstract type 'BBB'
file2.h:66: note: because the following virtual functions are pure within 'BBB':
file1.h:705: note: virtual nsresult AAA::funzione(void**)
come posso risolverlo? mi riporto qui sotto i file sorgenti e le corrispondenze
file1.h:705
file2.h:212
file.cpp
AAA = nsIRenderingContext
BBB = nsRenderingContextQt
CCC = nsDeviceContextQt
funzione = RetrieveCurrentNativeGraphicData
metodo = CreateRenderingContext
grazie!