NAME

       error_handler - Default system error handler.

DESCRIPTION

       This module defines what happens when certain types of errors occur.

EXPORTS

       raise_undef_exception(Module, Function, Args) -> no_return()

              Types:

                 Module = Function = atom()
                 Args = list()
                    A (possibly empty) list of arguments Arg1,..,ArgN

              Raises an undef exception with a stacktrace, indicating that Module:Function/N is undefined.

       undefined_function(Module, Function, Args) -> any()

              Types:

                 Module = Function = atom()
                 Args = list()
                    A (possibly empty) list of arguments Arg1,..,ArgN

              This  function is called by the runtime system if a call is made to Module:Function(Arg1,.., ArgN)
              and Module:Function/N is undefined. Notice that this function  is  evaluated  inside  the  process
              making the original call.

              This  function  first  attempts to autoload Module. If that is not possible, an undef exception is
              raised.

              If it is possible to load Module and function Function/N is exported, it is called.

              Otherwise,  if  function   '$handle_undefined_function'/2   is   exported,   it   is   called   as
              '$handle_undefined_function'(Function, Args).

          Warning:
              Defining  '$handle_undefined_function'/2 in ordinary application code is highly discouraged. It is
              very easy to make subtle errors that can take a long time to debug. Furthermore, none of the tools
              for   static   code   analysis   (such   as   Dialyzer   and   Xref)   supports   the    use    of
              '$handle_undefined_function'/2  and  no  such  support will be added. Only use this function after
              having carefully considered other, less dangerous, solutions. One example of potential  legitimate
              use is creating stubs for other sub-systems during testing and debugging.

              Otherwise an undef exception is raised.

       undefined_lambda(Module, Fun, Args) -> term()

              Types:

                 Module = atom()
                 Fun = function()
                 Args = list()
                    A (possibly empty) list of arguments Arg1,..,ArgN

              This  function  is  evaluated if a call is made to Fun(Arg1,.., ArgN) when the module defining the
              fun is not loaded. The function is evaluated inside the process making the original call.

              If Module is interpreted, the interpreter is invoked and  the  return  value  of  the  interpreted
              Fun(Arg1,.., ArgN) call is returned.

              Otherwise,  it  returns,  if  possible,  the value of apply(Fun, Args) after an attempt is made to
              autoload Module. If this is not possible, the call fails with exit reason undef.

NOTES

       The code in error_handler is complex. Do not  change  it  without  fully  understanding  the  interaction
       between the error handler, the init process of the code server, and the I/O mechanism of the code.

       Code changes that seem small can cause a deadlock, as unforeseen consequences can occur. The use of input
       is dangerous in this type of code.

Ericsson AB                                      kernel 8.5.4.2                              error_handler(3erl)