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Comment by slovenlyrobot | Hacker News Reader

These are used /everywhere/ in PostgreSQL, exactly for exception handling. The result isn't bad at all, but indeed, too powerful a tool for 99% of developers

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Fortunately, 99% of developers, like 99% of drivers, are better than average.

> 99% ... are better than average.

I'm thinking there's a flaw in your mathematics...

No flaw with math/stats here, that can actually happen. I think you're confusing average/mean with median (50-percentile).

PS: I'm not sure where he's getting his numbers though

I'm 99% sure that was tongue in cheek.

I think that it would have been even funnier to say that 99% of developers and 99% of drivers are better than the median, but I only figured this thanks to your parent's comment.

99% of the people on Earth have a higher than average number of legs.

And a below-average number of heads.

You've never been on a project that was 80% done and 80% to go?

And after the second 80% is finished, then you only have 80% left.

Not native speaker here, but I think, he just meant that, most programmers and drivers thinks they are better in respective things then, they really are.

It is just like letting programmer build a house. It is just a really bad idea.

https://insights.stackoverflow.com/survey/2019#evaluating-co...

> 70% of respondents say they are above average

Depends which average it refers to any of the means, or the media, or the mode can be “average” (most typically, though, it means the arithmetic mean), and it's only impossible in terms of the median.

Exactly. Anything where you have a main clump with a long tail will show this pattern--most samples will be better than the mean.

And Lua’s exceptions are somewhat odd because they are based on setjmp/longjmp. https://www.lua.org/manual/5.3/manual.html#4.6

Apparently they're also used for error handling in libpng. That's one of the reasons the libspng author started on their project.

And that's the perfect usage for goto. Error catching and jump to fail block...

Goto requires the fail block to be in the same frame. It can be a working error strategy for failing critical errors in such a way from a failing module. You have to be aware that lots of stuff is prone to leak (which can be avoided by i.e. using some memory arena) and locks/mutexes/... might be in unclear state, so code has to be aware of that.

The destination of the goto is usually the clean-up code.

That's nice for the single frame.

Let's take the example of PostgreSQL, which was mentioned in this thread: A potential implementation (I have no knowledge of pgsql internals) might be that for a single user session all memory is from a single arena, all locks and other handles are tied to the session handle, then it can be an efficient strategy to longjmp out on a critical error (i.e. IO error) and clean the arena as well as things tied to the session. instead of bubbling this up through all frames.

It's a different use case. There was a nice article[1] about exceptions in plain C with setjmp and longjmp.

[1] http://www.on-time.com/ddj0011.htm

You're in the 1% though right?

Funny way of saying "too error-prone for anyone sane to consider using".

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