NAME

       error_handler - Default System Error Handler

DESCRIPTION

       The error handler module defines what happens when certain types of errors occur.

EXPORTS

       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  run-time  system  if  a  call  is  made  to
              Module:Function(Arg1,..,  ArgN)  and  Module:Function/N  is  undefined.  Note  that
              undefined_function/3 is evaluated inside the process making the original call.

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

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

              Otherwise,  if  the function '$handle_undefined_function'/2 is exported, it will be
              called as '$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 will be raised.

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

              Types:

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

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

       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
              has been made to autoload Module. If this is not possible, the call fails with exit
              reason undef.

NOTES

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

       Changes in the code which may seem small can cause a deadlock as  unforeseen  consequences
       may occur. The use of input is dangerous in this type of code.