PostgreSQL's fsync() surprise

Of what interest is a portable program that is not useful? It's trivial to write a portable program; just check uname at the start and exit out on any but the system you're written for. Nobody does that, because it's not useful.

As for which parts may vary from version to version, version 3 may adhere to an entirely different standard than version 2. The fact that there is a standard may do you no good if it's evolving rapidly along with the software.

From the other side, even if you are standards conforming, that may not be enough. A user can expect that qsort sorts, but can they expect that it does so reasonably quickly? How often can you call fsync to maintain a reasonable balance between speed and safety? That's never going to be defined by the standard, but an understanding needs to be reached by the authors of a program like PostgreSQL.

I don't believe it's a question of abstract philosophy. It's one thing if standards were a tool used some places and not others in the computer world, that at their best were understood not to be sufficient to be binding on either implementer or user, then it would be reasonable to use unstandardized language in writing standards. But if _all_ APIs should depend on standards, then using an unstandardized language, when, again, formal languages like Lojban or simply standardized ones like French exist.