>>47No, it's not laziness. We found out it's not mandated by POSIX that the fclose-function should return an error in case the flush fails (yes, you read that right).
Glibc just behaves this way, and we only noticed that after testing with musl and discussing this with the musl-developers.
fshut() is the combination of literally a day's work of reading standards and applying best practices. A simple fclose() is not sufficient here.