Hacker News new | past | comments | ask | show | jobs | submit
Maxatar | on: C++ float-to-int conversion can be undefined behavior
How does a library writer testing that their library works with a specific version of a compiler that was already released have anything to do with a compiler implementation providing special treatment for that library?

Your interpretation contradicts the statement that "during development for a new release, MSVC were to land some changes that broke GSL, Microsoft's testing would catch that and ensure that the changes were reverted or fixed to support the latter, prior to shipping."

ranger_danger | parent
> How does a library writer testing that their library works with a specific version of a compiler that was already released have anything to do with a compiler implementation providing special treatment for that library?

Not special treatment for the library, but the library being able to assume that specific UB handling in certain existing compiler versions exists, can be relied on, and is compatible with the library's assumptions of such behavior, as long as those are the only versions they officially "support."

Maxatar | root | parent
Here is the original statement about special treatment:

"It was originally created by Microsoft and as Herb mentions "all our target platforms", so most likely it gets special treatment."

My claim is that Microsoft is not giving any special treatment to the GSL... the GSL is written using functionality that is officially available to any third party library, and hence not special.

Are you disputing this? If so then what is the special treatment you're claiming that Microsoft is giving to GSL or what special treatment is GSL making use of?

ranger_danger | root | parent
I am not claiming there is any special treatment at all. I think the situation is much simpler:

They (Microsoft) test GSL with specific compiler versions to observe how their usage of the UB is treated, and if satisfactory, that compiler version is now "supported" in their eyes. They do not claim to "support" any other version because they have not tested them to know how the UB functions there.

Maxatar | root | parent
What is the relationship between your claim, and the claim I replied to about GSL having special treatment? In other words, why did you reply to me with an interpretation about a post that claimed GSL is afforded special treatment by MSVC if your claim is that GSL does not get any special treatment from MSVC?

Did you intend to reply to someone else?