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Report From: Delphi-BCB/Compiler/Delphi/Language/Variants [ Add a report in this area ]

Report #: 99599

Status: Open

Variant does not fully support Extended type - FormatFloat or FloatToStrF Variant problem

Project: Delphi

Build #: 2010, XE

Version: 15.1

Submitted By: Hakan APAYDIN

Report Type: Suggestion / Enhancement Request

Date Reported: 10/4/2011 5:50:05 AM

Severity: Commonly encountered problem

Last Updated: 3/20/2012 2:24:39 AM

Platform: All versions

Internal Tracking #: 287994

Resolution: None (Resolution Comments)

Resolved in Build: : None

Duplicate of: None

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Description

Hello, please check this code. Last digit problem.

----------------
procedure TForm1.Button1Click(Sender: TObject);
var
aValue: Variant;
str: string;
begin
aValue := 11111111111111.1234;

str := FloatToStrF(aValue, ffFixed,18,4);
//result(NG): 11111111111111.1230
ShowMessage(str);

str := FormatFloat('.####', aValue);
//result(NG): 11111111111111.123
ShowMessage(str);
end;
----------------

----------------
procedure TForm1.Button2Click(Sender: TObject);
var
aValue: Extended;
str: string;
begin
aValue := 11111111111111.1234;

str := FloatToStrF(aValue, ffFixed,18,4);
//result(OK): 11111111111111.1234
ShowMessage(str);

str := FormatFloat('.####', aValue);
//result(OK): 11111111111111.1234
ShowMessage(str);
end;
----------------

Steps to Reproduce:

None

Workarounds

None

Attachment

None

Comments

Tomohiro Takahashi at 10/4/2011 6:21:09 AM -

I modified your code to clarify your case.

Hakan APAYDIN at 10/4/2011 6:34:07 AM -

Thank you for information. "variant" instead of "extended" is used are not a problem.

But third-party component used in the "variant" is a problem for use. component of the "variant" is not possible to make extended.

Tomohiro Takahashi at 10/4/2011 5:49:50 PM -

Thanks for your comment.
I changed [Type] and [Description] field as Sysop.

Tomohiro Takahashi at 10/4/2011 6:41:47 AM -

This case is related to _VarFromXXX and _VarToXXX functions in Variants unit.
-----------------
procedure _VarFromCurr;
begin
...
end;
...
procedure _VarFromReal;
begin
...
end;
...
function _VarToReal(const V: TVarData): Extended;
begin
  Result := _VarToDouble(V);
end;
...
...
function _VarToDouble(const V: TVarData): Double;
begin
  case V.VType of
    ...
    varCurrency: Result := V.VCurrency;
  ...
  ...
-----------------

Tomohiro Takahashi at 10/4/2011 6:58:54 AM -

Please see also documentation about Variant type.
[Variant Types (Delphi) - Variant Type Conversions]
http://docwiki.embarcadero.com/RADStudio/XE2/en/Variant_Types#Variant_Type_Conversions

and,
Extended type is 10-byte(80bit)
Real(Double) type is 8-byte(64bit)

Tomohiro Takahashi at 10/4/2011 7:03:02 AM -

Hakan-san
Do you want to put Extended variable into Variant type without loss?

Note:
With 64bit mode in Delphi XE2, Extended type is 8-byte(64bit).

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QualityCentral Delphi-BCB Compiler Delphi Language Default Parameters Dynamic Arrays Overloading Variants

Developer Tools

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QualityCentral

Delphi-BCB

Compiler

Delphi

Language

Default Parameters
Dynamic Arrays
Overloading
Variants