TPaxInvoke Methods

• Create
• Destroy
• LoadAddress
• ClearArguments
• AddArgAsByte
• AddArgAsWord
• AddArgAsCardinal
• AddArgAsShortInt
• AddArgAsSmallInt
• AddArgAsInteger
• AddArgAsInt64
• AddArgAsLongBool
• AddArgAsWordBool
• AddArgAsBoolean
• AddArgAsChar
• AddArgAsWideChar
• AddArgAsDouble
• AddArgAsSingle
• AddArgAsExtended
• AddArgAsCurrency
• AddArgAsAnsiString
• AddArgAsWideString
• AddArgAsShortString
• AddArgAsPChar
• AddArgAsPWideChar
• AddArgAsPointer
• AddArgAsRecord
• AddArgAsRecordByVal
• AddArgAsArray
• AddArgAsArrayByVal
• AddArgAsDynArray
• AddArgAsObject
• AddArgAsClassRef
• AddArgAsVariant
• AddArgAsSet
• AddArgAsInterface
• SetResultAsVoid
• SetResultAsByte
• SetResultAsWord
• SetResultAsCardinal
• SetResultAsShortInt
• SetResultAsSmallInt
• SetResultAsInteger
• SetResultAsBoolean
• SetResultAsWordBool
• SetResultAsLongBool
• SetResultAsChar
• SetResultAsWideChar
• SetResultAsDouble
• SetResultAsSingle
• SetResultAsExtended
• SetResultAsCurrency
• SetResultAsAnsiString
• SetResultAsWideString
• SetResultAsShortString
• SetResultAsPChar
• SetResultAsPWideChar
• SetResultAsPointer
• SetResultAsArray
• SetResultAsDynArray
• SetResultAsRecord
• SetResultAsObject
• SetResultAsClassRef
• SetResultAsInterface
• SetResultAsInt64
• CallHost
• GetResultPtr
• ClearResult

Constructor of TPaxInvoke class.

constructor Create(AOwner: TComponent); override;

Destructor of TPaxInvoke class.

destructor Destroy; override;

Loads dll and assigns address of a dll-defind functions to Address property.

procedure LoadAddress(const DllName, ProcName: String);

Example

PaxInvoke1.This := nil;
PaxInvoke1.CallConv := _ccMSFASTCALL;
PaxInvoke1.LoadAddress('CppDll.dll', 'cube');
PaxInvoke1.ClearArguments;
PaxInvoke1.AddArgAsInteger(2);
PaxInvoke1.SetResultAsInteger;
PaxInvoke1.CallHost; 
ShowMessage(IntToStr(Integer(PaxInvoke1.GetResultPtr^)));

Clears arguments.

procedure ClearArguments;

Example

function TForm1.Test(X, Y: Integer): Integer; stdcall;
begin
  result := X + Y;
end;

procedure TForm1.Button7Click(Sender: TObject);

function P(X, Y: Currency): String; stdcall;
begin
  result := CurrToStr(X + Y);
end;

begin
  PaxInvoke1.This := nil; // this is not a method
  PaxInvoke1.CallConv := _ccSTDCALL;
  PaxInvoke1.Address := @P;
  PaxInvoke1.ClearArguments;
  PaxInvoke1.AddArgAsCurrency(2.2);
  PaxInvoke1.AddArgAsCurrency(3.4);
  PaxInvoke1.SetResultAsAnsiString;
  PaxInvoke1.CallHost; // call host-defined function
  ShowMessage(String(PaxInvoke1.GetResultPtr^));
  PaxInvoke1.ClearResult;

  PaxInvoke1.This := Self; // this is a method
  PaxInvoke1.CallConv := _ccSTDCALL;
  PaxInvoke1.Address := @TForm1.Test;
  PaxInvoke1.ClearArguments;
  PaxInvoke1.AddArgAsInteger(2);
  PaxInvoke1.AddArgAsInteger(3);
  PaxInvoke1.SetResultAsInteger;
  PaxInvoke1.CallHost; 
  ShowMessage(IntToStr(Integer(PaxInvoke1.GetResultPtr^)));
end;

Adds argument of Byte type.

procedure AddArgAsByte(value: Byte);

Adds argument of Word type.

procedure AddArgAsWord(value: Word);

Adds argument of Cardinal type.

procedure AddArgAsCardinal(value: Cardinal);

Adds argument of ShortInt type.

procedure AddArgAsShortInt(value: ShortInt);

Adds argument of SmallInt type.

procedure AddArgAsSmallInt(value: SmallInt);

Adds argument of Integer type.

procedure AddArgAsInteger(value: Integer);

Adds argument of Int64 type.

procedure AddArgAsInt64(value: Int64);

Adds argument of LongBool type.

procedure AddArgAsLongBool(value: LongBool);

Adds argument of WordBool type.

procedure AddArgAsWordBool(value: WordBool);

Adds argument of Boolean type.

procedure AddArgAsBoolean(value: Boolean);

Adds argument of Char type.

procedure AddArgAsChar(value: Char);

Adds argument of WideChar type.

procedure AddArgAsWideChar(value: WideChar);

Adds argument of Double type.

procedure AddArgAsDouble(value: Double);

Adds argument of Single type.

procedure AddArgAsSingle(value: Single);

Adds argument of Extended type.

procedure AddArgAsExtended(value: Extended);

Adds argument of Currency type.

procedure AddArgAsCurrency(value: Currency);

Adds argument of AnsiString type.

procedure AddArgAsAnsiString(const value: AnsiString);

Adds argument of WideString type.

procedure AddArgAsWideString(const value: WideString);

Adds argument of ShortString type.

procedure AddArgAsShortString(const value: ShortString);

Adds argument of PChar type.

procedure AddArgAsPChar(value: PChar);

Adds argument of PWideChar type.

procedure AddArgAsPWideChar(value: PWideChar);

Adds argument of Pointer type.

procedure AddArgAsPointer(value: Pointer);

Adds argument of a Record type.

procedure AddArgAsRecord(var value; Size: Integer);

Adds argument of a record type. Argument is passed by value.

procedure AddArgAsRecordByVal(var value; Size: Integer);

Adds argument of array type.

procedure AddArgAsArray(var value; Size: Integer);

Adds argument of array type. Argument is passed by value.

procedure AddArgAsArrayByVal(var value; Size: Integer);

Adds argument of a dynamic array type.

procedure AddArgAsDynArray(var value);

Adds argument of a class type.

procedure AddArgAsObject(value: TObject);

Adds argument of a class reference type.

procedure AddArgAsClassRef(value: TClass);

Adds argument of Variant type.

procedure AddArgAsVariant(const value: Variant);

Adds argument of a set type.

procedure AddArgAsSet(var value; Size: Integer);

Adds argument of an interface type.

procedure AddArgAsInterface(const value: IUnknown);

Sets result type as void type (for procedures).

procedure SetResultAsVoid;

Sets result type as Byte type.

procedure SetResultAsByte;

Sets result type as Word type.

procedure SetResultAsWord;

Sets result type as Cardinal type.

procedure SetResultAsCardinal;

Sets result type as ShortInt type.

procedure SetResultAsShortInt;

Sets result type as SmallInt type.

procedure SetResultAsSmallInt;

Sets result type as Integer type.

procedure SetResultAsInteger;

Sets result type as Boolean type.

procedure SetResultAsBoolean;

Sets result type as WordBool type.

procedure SetResultAsWordBool;

Sets result type as LongBool type.

procedure SetResultAsLongBool;

Sets result type as Char type.

procedure SetResultAsChar;

Sets result type as WideChar type.

procedure SetResultAsWideChar;

Sets result type as Double type.

procedure SetResultAsDouble;

Sets result type as Single type.

procedure SetResultAsSingle;

Sets result type as Extended type.

procedure SetResultAsExtended;

Sets result type as Currency type.

procedure SetResultAsCurrency;

Sets result type as AnsiString type.

procedure SetResultAsAnsiString;

Sets result type as WideString type.

procedure SetResultAsWideString;

Sets result type as ShortString type.

procedure SetResultAsShortString;

Sets result type as PChar type.

procedure SetResultAsPChar;

Sets result type as PWideChar type.

procedure SetResultAsPWideChar;

Sets result type as a pointer type.

procedure SetResultAsPointer;

Sets result type as an array type.

procedure SetResultAsArray(Size: Integer);

Sets result type as a dynamic array type.

procedure SetResultAsDynArray;

Sets result type as a record type.

procedure SetResultAsRecord(Size: Integer);

Sets result type as a class type.

procedure SetResultAsObject;

Sets result type as a class reference type.

procedure SetResultAsClassRef;

Sets result type as an interface type.

procedure SetResultAsInterface;

Sets result type as Int64 type.

procedure SetResultAsInt64;

Calls a host-defined function or method.

procedure CallHost;

Returns pointer to a result value.

function GetResultPtr: Pointer;

You have to apply the type cast to extract a result value.

Example

type
  TCharRec = record
    X, Y: Char;
  end;

function MyHostFunc(const U, V: TCharRec): String; stdcall;
begin
  result := U.X + V.Y;
end;

var
  R: TCharRec;
  S: String;
begin
  R.X := 'a';
  R.Y := 'b';

  PaxInvoke1.Address := @ MyHostFunc;
  PaxInvoke1.This := nil; // this is not a method, but global function
  PaxInvoke1.ClearArguments;
  PaxInvoke1.AddArgAsRecord(R, SizeOf(R));
  PaxInvoke1.AddArgAsRecord(R, SizeOf(R));
  PaxInvoke1.SetResultAsAnsiString;
  PaxInvoke1.CallConv := _ccSTDCALL;
  PaxInvoke1.CallHost; // call host-defined function
  S := String(PaxInvoke1.GetResultPtr^);
  ShowMessage(S);

If result type is a dynamic type such as AnsiString, Interface, Variant or dynamic array, you have to apply the ClearResult method to avoid a memory leak.

procedure ClearResult;

Example

type
  ITest = interface
  ['{E7AA427A-0F4D-4A96-A914-FAB1CA336337}']
    procedure Proc(const S: String);
  end;

  TTest = class(TInterfacedObject, ITest)
  public
    procedure Proc(const S: String);
  end;

procedure TTest.Proc(const S: String);
begin
  ShowMessage(S);
end;

function GetIntf(I: ITest): ITest;
begin
  if Assigned(I) then
    result := I
  else
    result := TTest.Create;
end;

var
  I, J: ITest;
begin
  J := TTest.Create;
  
  PaxInvoke1.This := nil; // this is not a method
  PaxInvoke1.CallConv := _ccREGISTER;
  PaxInvoke1.Address := @GetIntf;
  PaxInvoke1.ClearArguments;
  PaxInvoke1.AddArgAsInterface(J);
  PaxInvoke1.SetResultAsInterface;
  PaxInvoke1.CallHost; // call host-defined function
  IUnknown(I) := IUnknown(PaxInvoke1.GetResultPtr^);
  I.Proc('hello');

  PaxInvoke1.ClearResult; // IUnknown(PaxInvoke1.GetResultPtr^)._Release;
end;