[Patch] libstdc++/20787 (DR 130)

[Gabriel Dos Reis]

Geoffrey Keating <geoffk@geoffk.org> writes:

| Paolo Carlini <pcarlini@suse.de> writes:
| 
| > Hi,
| > 
| > a few days ago I noticed that the relevant DR in the meanwhile has been
| > moved to [DR] status and decided to reconsider implementing its
| > resolution. Indeed, apparently there is a very large consensus (see also
| > Effective STL, outside the LWG references proper, f.i.) that changing
| > the associative containers consistently with all the other containers is
| > a good thing. The only minor disadvantage seems that a single
| > erase(iterator) becomes computationally a little more expensive, due to
| > the additional iterator increment (however, this is not the case for
| > erase(iterator, iterator), because its internal loop can now make use of
| > the erase(iterator) return value, i.e., the very same idiom used in
| > list::erase).
| > 
| > Anyone disagreeing with adding the below to mainline?!?
| 
| Isn't this a binary incompatible change?

It is.

| > -      void
| > +      iterator
| >        erase(iterator __position)
| > -      { _M_t.erase(__position); }
| > +      { return _M_t.erase(__position); }
| 
| It might happen to be OK on some platforms, but I doubt it would be
| safe on all.

indeed, ABI-compabitility-wise.

-- Gaby