For dynamic library how to write characters together? Masters problems to solve, be urgent!!!

CodePudding user response:

http://embarcadero.newsgroups.archived.at/public.delphi.nativeapi/201103/1103314922.html

DLL:

 
The library Project1. 

{Important note about DLL memory management: ShareMem must be the 
The first unit in your library 's USES clause AND your project' s (select 
The Project - the View Source) USES clause if your DLL exports any procedures or 
Functions provides 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 get the using BORLNDMM. DLL, pass the string information 
Using PChar or ShortString parameters.} 

USES the 
Forms, 
SysUtils, 
Unit1 in 'Unit1. Pas' {fmMain}; 

{$R *. Res} 

The function JoinString (stringOne, stringTwo: PChar) : PChar; Export; Stdcall; 
Var 
Buffer: PChar; 
The begin 
GetMem (Buffer, Length (stringOne) + Length (stringTwo) + 1); 
StrCopy (Buffer, PChar (stringOne)); 
SysUtils. StrCat (Buffer, stringTwo); 
Result:=Buffer; 
FreeMem (Buffer); 
end; 

Exports 
JoinString; 

The begin 
End. 

Call:

 
The unit Unit2. 

Interface 

USES the 
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, 
Dialogs, StdCtrls; 

Type 
TForm1=class (TForm) 
For: 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} 

The function JoinString (stringOne, stringTwo: PChar) : PChar; Export; Stdcall; External 'Project1. DLL'; 

Procedure TForm1. Button2Click (Sender: TObject); 
The begin 
Memo1. Lines. The Add (JoinString (PChar (Edit1. Text), PChar (Edit2. Text))); 
end; 

End. 

CodePudding user response:

Actually can use WideString directly this is the format of Microsoft, nor the memory manager management by Delphi.
He is OLE with API SysAllocStrLen BSTR is distributed.