On 10/1/18 4:58 PM, Ion Gaztañaga via Boost wrote:

Hi,

My libraries have supported quite old compilers, starting from Visual 2003 and GCC 3.4 and I'm asking for feedback before I start dropping old compilers. The number of supported plus locally+regression tested versions has increased a lot these years and that's a lot of work with reduced benefits.

My first idea is to drop anything older than 10 years, which means that the minimum will be MSVC 9.0 and GCC 4.3 (both released in 2008).

Thoughts, problems, comments?

I don't think there is any significant demand for ancient compilers like MSVC 7.1 or gcc < 4.1, so I'm perfectly fine with dropping them. Your list of supported compilers looks ok to me, even a little on the conservative side. I would drop gcc 4.3 as well, despite it is used in SLES 11. Old enterprise distros are not very representative, since new Boost releases are unlikely to be used there anyway.

Ion Gaztañaga wrote:

My first idea is to drop anything older than 10 years, which means that the minimum will be MSVC 9.0 and GCC 4.3 (both released in 2008).

A good heuristic is to not support anything not present on Travis and Appveyor, which at the moment translates to GCC 4.4, Clang 3.3 and MSVC 9.0. This is very close to what you've chosen. (As a general observation, pull requests that break GCC < 5, MSVC < 12.0 often get merged, so Boost overall isn't likely to work very well on them, although individual libraries might. The Travis superproject build is catching some of the GCC 4.8 issues, but not all, and GCC 4.4 and 4.6 are being paid close to no attention.)

As you probably know, I'm not a boost library maintainer myself, but have been pushing for boost to shed old cruft (e.g. dropping c++03 support in boost completely), so take the following with a grain of salt:

-----Original Message----- From: Boost On Behalf Of Ion Gaztañaga via Boost Sent: Monday, October 1, 2018 3:59 PM

[...]

I've reviewed some popular long support Linux distributions:

-> RHEL 6 uses GCC 4.4. -> SUSE Linux Enterprise Server 11 Service Pack 4 (SP4) uses GCC 4.3

As Andrey said, I wouldn't be too concerned with old enterprise distros. The users that do want to use new boost releases on those distributions actually have supported access to more recent toolchains via sdks/development tools. Personally I would focus on the default compiler versions on distributions that are still within their regular support period when you actually drop the support. (E.g. SUSE LES 11 will enter extended support on April 2019, so I'd rather look at SUSE LES 12 and RHEL 7 for the same reason) Don't forget the pipeline delay here: - You probably want to give a warning that compiler version X.Y will no longer be supported in boost version 1.W one or two releases in advance (1.W-1 or even 1.W-2 ). - When boost 1.W is released, it will take some time until it is made available to the developers writing applications for those platforms (e.g. due to company internal testing and upgrade cycles) - The user of your library might have a release cycle of their own - Finally, the user of the application using boost 1.W will have an upgrade cycle of their own an probably not employ the new software version the day it is released. This is of course the worst case scenario and it depends e.g. on whether your library is used in an in-house application or a sold software product, but there may easily be 1-x years between the point that you decide you want to drop support for toolchain version X.Y and the point when an application using your library actually would be deployed on a production system using that toolchain. Finally, boost is open source and free - if a company really wants to use a long-outdated c++ toolchain with the latest version of boost, they can pay someone to implement the necessary workarounds. So unless you are getting payed to support those libraries, you don't have to feel too bad if you make your life a little easier. If supporting gcc4.4 or VS2008 doesn't cost you much time and effort: Great! Keep supporting them! Otherwise, better switch to something more recent and invest the saved time on new features, other improvements or just life with your family. Best Mike