http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59182
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution|--- |INVALID
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to sequoiahead from comment #0)
> The problem is that the compiler is able to convert void Func::pfunc(int) to
> std::function<void(int)>, but can't convert void Func::func() to
> std::function<void()>
No, that's not what's happening.
std::bind(&Func::pfunc, fInstance, std::placeholders::_1) returns a function
object, call it B1, that takes a single argument, as indicated by the
placeholder. B1 is convertible to function<void(int)>, because that type takes
also a single argument, so will pass its argument to B1.
B1 is not convertible to function<void()> because you have to call a
function<void()> with no arguments, and B1 cannot be called with no arguments.
std::function is rejecting your program because it's invalid. std::bind
doesn't do the same checking, so doesn't reject it, but your program is still
invalid.
This compiles OK:
std::function<void()> voidMemberFunc = std::bind(&Func::func, fInstance);
This bind expression creates a function object that takes no arguments, so can
be stored in a function<void()>.
