Question

Suppose I have something like this :

try code_that_fails()
catch _:_ -> .....

How do I print the stacktrace in the catch block? That block catches all exceptions, but I don’t know how to print the stack…

Can you help me?

Answer 1

From Erlang 21.0 onwards, there’s a new official way to get the stack trace. An optional pattern match in the try expression on the third parameter in the exception, which will contain the stack trace:

try
   code_that_fails()
catch
   _:_:Stacktrace ->
      erlang:display(Stacktrace)
end

Older versions (OTP 20 and below)

For versions of Erlang/OTP 20 and below, you need to use get_stacktrace/0, which allows you to get the stacktrace of the last exception in the calling process:

try
   code_that_fails()
catch
   _:_ ->
      erlang:display(erlang:get_stacktrace())
end