DLL/Lib: Parameter Validierung

[himitsu]

Exceptions gibt es im C auch, nur kennt C natürlich die Delphi-Exceptionklassen nicht und kann da dann nichtmal den im unbekannten Message-Text auswerten.

Nja, du kannst natürlich auch LongBool-Results nehmen (in C++ ist der BOOL gern 32 Bit groß),
definierst dir eine Reihe Fehlercodes, nach dem Muster der WinAPI, wie z.B. HRESULT,
und nutzt fleißig SetLastError. (natürlich nur wenn es auch einen Fehler gab, also nur bei Result=False)

FACILITY ist ein Code für deine Komponente/Library.

Delphi-Quellcode:

{------------------------------}
{     OLE Error Codes          }
{------------------------------}

(*
  The return value of OLE APIs and methods is an HRESULT.
  This is not a handle to anything, but is merely a 32-bit value
  with several fields encoded in the value.  The parts of an
  HRESULT are shown below.

  HRESULTs are 32 bit values layed out as follows:

   3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
   1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
  +-+-+-+-+-+---------------------+-------------------------------+
  |S|R|C|N|r|    Facility         |               Code            |
  +-+-+-+-+-+---------------------+-------------------------------+

  where

      S - Severity - indicates success/fail
          0 - Success
          1 - Fail (COERROR)

      R - reserved portion of the facility code, corresponds to NT's
              second severity bit.

      C - reserved portion of the facility code, corresponds to NT's
              C field.

      N - reserved portion of the facility code. Used to indicate a
              mapped NT status value.

      r - reserved portion of the facility code. Reserved for internal
              use. Used to indicate HRESULT values that are not status
              values, but are instead message ids for display strings.

      Facility - is the facility code

      Code - is the facility's status code
*)

const
  SEVERITY_SUCCESS = 0;
  SEVERITY_ERROR = 1;

function Succeeded(Status: HRESULT): BOOL; inline;
function Failed(Status: HRESULT): BOOL; inline;
function IsError(Status: HRESULT): BOOL; inline;
function HResultCode(hr: HRESULT): Integer; inline;
function HResultFacility(hr: HRESULT): Integer; inline;
function HResultSeverity(hr: HRESULT): Integer; inline;
function MakeResult(sev, fac, code: Integer): HResult; inline;

const
  { HRESULT value definitions }
  { Codes $4000-$40ff are reserved for OLE }

  S_OK    = $00000000;
  S_FALSE = $00000001;

  NOERROR = 0;

  E_UNEXPECTED = HRESULT($8000FFFF);
  E_NOTIMPL = HRESULT($80004001);
  E_OUTOFMEMORY = HRESULT($8007000E);
  E_INVALIDARG = HRESULT($80070057);
  E_NOINTERFACE = HRESULT($80004002);
  ...

oder

Delphi-Quellcode:

{ DOS and OS/2 Compatible Error Code definitions returned by the Win32 Base
  API functions. }


{ Translated from WINERROR.H }
{ Error code definitions for the Win32 API functions }

(*
  Values are 32 bit values layed out as follows:
   3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
   1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
  +---+-+-+-----------------------+-------------------------------+
  |Sev|C|R|     Facility          |               Code            |
  +---+-+-+-----------------------+-------------------------------+

  where
      Sev - is the severity code
          00 - Success
          01 - Informational
          10 - Warning
          11 - Error

      C - is the Customer code flag
      R - is a reserved bit
      Facility - is the facility code
      Code - is the facility's status code
*)

{ Define the facility codes }

const
  FACILITY_WINDOWS                     = 8;
  {$EXTERNALSYM FACILITY_WINDOWS}
  FACILITY_STORAGE                     = 3;
  {$EXTERNALSYM FACILITY_STORAGE}
  FACILITY_RPC                         = 1;
  {$EXTERNALSYM FACILITY_RPC}
  FACILITY_SSPI                        = 9;
  {$EXTERNALSYM FACILITY_SSPI}
  FACILITY_WIN32                       = 7;
  {$EXTERNALSYM FACILITY_WIN32}
  FACILITY_CONTROL                     = 10;
  {$EXTERNALSYM FACILITY_CONTROL}
  FACILITY_NULL                        = 0;
  {$EXTERNALSYM FACILITY_NULL}
  FACILITY_INTERNET                    = 12;
  {$EXTERNALSYM FACILITY_INTERNET}
  FACILITY_ITF                         = 4;
  {$EXTERNALSYM FACILITY_ITF}
  FACILITY_DISPATCH                    = 2;
  {$EXTERNALSYM FACILITY_DISPATCH}
  FACILITY_CERT                        = 11;
  {$EXTERNALSYM FACILITY_CERT}

{ Define the severity codes }

  ERROR_SUCCESS = 0;
  NO_ERROR = 0;

  ERROR_INVALID_FUNCTION = 1;
  ERROR_FILE_NOT_FOUND = 2;
  ERROR_PATH_NOT_FOUND = 3;
  ERROR_TOO_MANY_OPEN_FILES = 4;
  ...