[Bug libstdc++/56551] New: A faster implementation of std::function

[Bug libstdc++/56551] New: A faster implementation of std::function

[marton78 at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56551

             Bug #: 56551
           Summary: A faster implementation of std::function
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: libstdc++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: marton78@gmail.com


It would be great if the clever implementation of std::function presented on
the following page could find its way into libstdc++.

http://probablydance.com/2013/01/13/a-faster-implementation-of-stdfunction/

> The code is in the public domain (I want all library writers to start using it)
> and here is a download link: http://dl.dropbox.com/u/27990997/function.h

[Bug libstdc++/56551] A faster implementation of std::function

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56551

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2013-03-06 16:24:20 UTC ---
I've only glanced at the code but it's good to see you support passing an
Allocator to the constructor (though it should use std::allocator_traits to
support C++11 allocators)

I was thinking of making some big changes to our std::function for GCC 4.9 in
order to support custom allocators.

[Bug libstdc++/56551] A faster implementation of std::function

[malteskarupke at web dot de]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56551

malteskarupke at web dot de changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |malteskarupke at web dot de

--- Comment #2 from malteskarupke at web dot de 2013-03-09 23:17:03 UTC ---
I've uploaded a new version that uses std::allocator_traits. It's behind the
same download link as before.

[Bug libstdc++/56551] A faster implementation of std::function

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56551

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rockeet at gmail dot com

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
*** Bug 106871 has been marked as a duplicate of this bug. ***

[Bug libstdc++/56551] A faster implementation of std::function

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56551

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
As I just wrote on the duplicate bug:

I've looked into this and I don't think it can be done without an ABI break.
Objects constructed in old code compiled by an older GCC would still have a
null pointer, so code compiled by a new GCC can't assume that the pointer is
never null.