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0 pointsKerrAvon4mo ago0 comments

For one thing, they’re expensive and viral. “Zero overhead” implementations don’t take into account the need for unwind tables. For every function/method that might be thrown across. They’re disabled in a lot of production environments for this reason.

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neonz804mo ago

There was an interesting talk about C++ exceptions in smaller firmware at CppCon last year: https://youtu.be/bY2FlayomlE

Basically, the overhead of exceptions is probably less than handling the same errors manually in any non-trivial program.

Also, it's not like these table doesn't exist in other languages. Both Rust and Go have to unwind.

amelius4mo ago

But if you explicitly handle exceptions using IF statements then that's overhead too, right?

arbitrandomuser4mo ago

yes but i think branch prediction essentialy makes them zero overhead

neonz804mo ago

That's a different type of overhead than having unwind tables. With exceptions you wouldn't need a branch after each function call at all.

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0 pointsKerrAvon4mo ago0 comments

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neonz804mo ago

There was an interesting talk about C++ exceptions in smaller firmware at CppCon last year: https://youtu.be/bY2FlayomlE

Basically, the overhead of exceptions is probably less than handling the same errors manually in any non-trivial program.

Also, it's not like these table doesn't exist in other languages. Both Rust and Go have to unwind.

amelius4mo ago

But if you explicitly handle exceptions using IF statements then that's overhead too, right?

arbitrandomuser4mo ago

yes but i think branch prediction essentialy makes them zero overhead

neonz804mo ago

That's a different type of overhead than having unwind tables. With exceptions you wouldn't need a branch after each function call at all.

1 more reply

j / k navigate · click thread line to collapse