trusty (3) error_handler.3erl.gz

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.