memstream: return the internal string in vlc_memstream_close()

It's NULL in case there's an error. We don't need an error code for that.

In many case the result is just returned the same way without touching the vlc_memstream anymore.

We can keep the VLC_USED and even add VLC_MALLOC for these return values.

changed milestone to %4.0

added Component::Core label

added MRStatus::Reviewable label

Reference !4585 (comment 417984)

And not using VLC_USED might lead for forgetting checking the error. So I might drop these patches

I'm not a fan either, vlc_memstream works like an error monad which resolves into an error and a buffer in the end. Mixing both means that error can be ignored without it being visible in the code.

This is by design supposed to work like the standard in memory stream. Last I checked fclose() returns an error status not a pointer.

In this case the implementation cannot be used as the original open_memstream implementation (remove the vlc_memstream_ prefix and replace vlc_memstream by FILE on Linux and see what happens when you compile).

IMO we should follow standards when they are convenient. The fact you had to use a custom structure to re-implement it means the design was probably not that good to start with. And we end up being tied to a design that's impracticle for us, and then blocking usage that would be cleaner that the original design and/or more adapted to our (portable) use.

added MRStatus::InReview label and removed MRStatus::Reviewable label

mentioned in merge request !4588 (merged)

closed