--Copyright:      Matra Datavision 1992,1993

-- File:          OSD_Error.cdl
-- Created:       May 18 1992
-- Author:        Stephan GARNAUD (ARM)
--                <sga@sparc4>


class Error from OSD

   ---Purpose: Management of OSD errors

--  Error handling style example:
--
--
--  try{
--  .
--  .
--  .
--  OSD_Semaphore mysem("KeyName"); 
--  if (mysem.Failed()) 
--   switch (mysem.Error()){
--    case 201: mysem.Perror();
--    case 202: cout << "Just a warning";
--   }
--  .
--  .
--  .
--  }
--  catch(Standard_Failure){
--   Handle(Standard_Failure) Occur = Standard_Failure::Caught();
--   .
--   .  // Programmer's decision
--   .
--
--  Each method can be error tested with object.Failed().
--  To manage an occuring error, just use object.Perror(); 
--
--  It is possible to reset the error counter to zero.
--  To do this use the 'Reset' method .


--  Only 4 methods are usable for programmer :
--      Failed   to see whether an error occured or not.
--      Value    to get system independent error code.
--               (See annexe for a complete list of error code).
--      Reset    to reset error code to zero (no error).
--      Perror   to raise OSDError and print a self explanatory error
--               message. This message says why an error occurs and
--               explains what to do to correct it.

uses
  WhoAmI, AsciiString from TCollection

raises
  OSDError 

is
 Create returns Error;
   ---Purpose: Initializes Error to be without any Error.
   --          This is only used by OSD, not by programmer.
   ---Level: Public

 Perror (me : in out)
   ---Purpose: Raises OSD_Error with accurate error message.
   raises OSDError is static;
   ---Level: Public

 SetValue (me : in out; Errcode : Integer; From : Integer; Message : AsciiString) is static;
   ---Purpose: Instantiates error
   --          This is only used by OSD methods to instantiates an error code.
   --          No description is done for the programmer.
   ---Level: Public

 Error (me) returns Integer is static;
   ---Purpose: Returns an accurate error code.
   --          To test these values, you must include "OSD_ErrorList.hxx"
   ---Level: Public


 Failed (me) returns Boolean is static;
   ---Purpose: Returns TRUE if an error occurs
   --          This is a way to test if a system call succeeded or not.
   ---Level: Public

 Reset (me : in out) is static;
   ---Purpose: Resets error counter to zero
   --          This allows the user to ignore an error (WARNING).
   ---Level: Public

fields
   myMessage : AsciiString;   -- Internal error message
   myErrno   : Integer;  -- UNIX/VMS error used by OSD only
   myCode    : WhoAmI;   -- Accuracy code in error for OSD only
   extCode   : Integer;  -- Error type decoded for user
end Error from OSD;