Fix initGenericErrorDefaultFunc(NULL) Calling initGenericErrorDefaultFunc(NULL) currently yields to /usr/include/libxml2/libxml/xmlerror.h:23:45: error: invalid use of void expression 23 | xmlSetGenericErrorFunc(NULL, (h) ? *(h) : NULL) Indeed, even if h is nul, the compiler will try to give a type to *(h), which can't work.