Why does debugging "pure virtual method called" have to be so hard?

[Alexandre Oliva]

Jason Merrill <jason@cygnus.com> writes:

>>>>>> Mike Stump <mrs@wrs.com> writes:
>> How to others feel about calling abort instead of _exit?  abort might
>> be more useful.

> I would prefer terminate.

But [lib.terminate] says:

1 Called by the implementation when exception handling must be abandoned
  for any of several reasons (_except.terminate_).  May also  be  called
  directly by the program.

Calling a pure virtual function is not a case of exception handling,
so it might be strange to call it in such a situation.  Of course, one 
may argue that calling a pure virtual function has undefined behavior, 
and so it *may* call terminate(), but that's not what one would
expect, so I'd rather modify __pure_virtual() so that it calls abort() 
or throws an exception of some non-standard type, say,
__pure_virtual_exception, which may end up turning into a call of
unexpected(), then terminate().

-- 
Alexandre Oliva
mailto:oliva@dcc.unicamp.br mailto:oliva@gnu.org mailto:aoliva@acm.org
http://www.dcc.unicamp.br/~oliva
Universidade Estadual de Campinas, SP, Brasil