求字符相加的動態庫如何寫？各位高手麻煩解答下，急啊！！！
uj5u.com熱心網友回復：
http://embarcadero.newsgroups.archived.at/public.delphi.nativeapi/201103/1103314922.htmlDLL：
library Project1;
{ Important note about DLL memory management: ShareMem must be the
first unit in your library's USES clause AND your project's (select
Project-View Source) USES clause if your DLL exports any procedures or
functions that pass strings as parameters or function results. This
applies to all strings passed to and from your DLL--even those that
are nested in records and classes. ShareMem is the interface unit to
the BORLNDMM.DLL shared memory manager, which must be deployed along
with your DLL. To avoid using BORLNDMM.DLL, pass string information
using PChar or ShortString parameters. }
uses
Forms,
SysUtils,
Unit1 in 'Unit1.pas' {fmMain};
{$R *.res}
function JoinString(stringOne, stringTwo : PChar ) : PChar; export; stdcall;
var
Buffer: PChar;
begin
GetMem(Buffer,Length(stringOne) + Length(stringTwo) + 1);
StrCopy(Buffer, PChar(stringOne));
SysUtils.StrCat(Buffer, stringTwo);
Result := Buffer;
FreeMem(Buffer);
end;
exports
JoinString;
begin
end.
呼叫：
unit Unit2;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TForm1 = class(TForm)
Button1: TButton;
Edit1: TEdit;
Edit2: TEdit;
Memo1: TMemo;
Button2: TButton;
procedure Button2Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
function JoinString(stringOne, stringTwo : PChar ) : PChar; export; stdcall; external 'Project1.dll';
procedure TForm1.Button2Click(Sender: TObject);
begin
Memo1.Lines.Add(JoinString(PChar(Edit1.Text), PChar(Edit2.Text)));
end;
end.
uj5u.com熱心網友回復：
其實可以直接用WideString這個是微軟的格式,也不受Delphi的記憶體管理器管理.他是OLE的BSTR是用SysAllocStrLen這類API分配的.
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標籤：語言基礎/算法/系統設計