[Development] Summary ABI compabilty

Giuseppe D'Angelo dangelog at gmail.com
Tue Nov 22 19:21:40 CET 2016


On Tue, Nov 22, 2016 at 12:33 PM, Marco Bubke <Marco.Bubke at qt.io> wrote:
> I think I miss some but feel free to extend the list

Does Qt need to keep BC across incompatible standard C++ library
implementations? (Independently from the long term/short term ABI
breaks)

This does not mean "is Qt affected by a BC break in the standard C++
library that you used to compile Qt", the answer to that is yes (Qt
uses the standard library internally).

* pros:
** You can use Qt compiled against either libc++ or libstdc++, with
"the other one", without recompiling Qt.

* cons:
** End users applications using anything coming from the standard
library still need to be recompiled; what's the problem at recompiling
Qt too? (If the end user application is NOT using the standard library
then this whole discussion is void)
** We can't expose std:: datatypes in our ABI, only in inline
functions, losing significant functionality (and possibly performance)

* subjective cons:
** apart from Qt, noone does that, why should Qt be special in that regard?
** is there anyone really using this feature?

Cheers,
-- 
Giuseppe D'Angelo



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