Delphi Programming Unleashed/Delphi_Programming_Unleashed_SAMS_Publishing_1995.iso/chap15/pcharfun/main.pas

Pascal/Delphi Source File | 1995-03-20 | 999b | 57 lines

unit Main;

{ Program copyright (c) 1995 by Charles Calvert }
{ Project Name: }

{ This program demonstrates how to retrieve a
  PChar from a function. The key point is that
  you should never allocate memory for the PChar
  from inside the called function, but should
  first allocate memory, pass the string to a
  function, and then change the string that
  has been passed in. }

interface

uses
  WinTypes, WinProcs, Classes,
  Graphics, Forms, Controls,
  StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Edit1: TEdit;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

uses
  SysUtils;

{$R *.DFM}

procedure GetDate(Date: PChar);
begin
  StrCopy(Date, '11/01/94');
end;


procedure TForm1.Button1Click(Sender: TObject);
var
  S: array[0..100] of char;
begin
  GetDate(S);
  Edit1.Text := S;
end;

end.