Erlang / Erlang Advanced Interview questions

What is the difference between error, exit, and throw in Erlang?

All three raise an exception that unwinds the call stack until caught, but they carry different intent and default severity.

error/1	exit/1	throw/1
Signals a programming/runtime error; includes a stack trace; typically left uncaught to crash the process.	Signals intentional process termination; propagates to linked processes as an exit signal.	A lightweight, expected non-local return; meant to be caught by the same code that anticipated it.

try
    error(bad_input)   %% class = error
catch
    error:Reason -> handle(Reason);
    exit:Reason  -> handle_exit(Reason);
    throw:Reason -> handle_throw(Reason)
end.

The rule of thumb: use throw for expected, local control flow inside code you also control the catch for; use error for genuine bugs you want visible in crash logs with a stack trace; use exit when you specifically want to terminate a process and have that termination propagate to anything linked to it.

Take quiz

Which exception class is typically used for expected, local non-error control flow? error

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exit

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throw

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Which exception class propagates as an exit signal to linked processes? exit

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throw

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Only error does this

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Erlang / Erlang Advanced Interview questions

What is the difference between error, exit, and throw in Erlang?

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