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POPlease help how to Convert C code to Delphi code (qsBarcode)
 

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    <p>I need to use a DLL file from qsBarcode <a href="http://www.qsbarcode.de/en/index.htm" rel="nofollow">http://www.qsbarcode.de/en/index.htm</a> (here is the download link <a href="http://www.qsbarcode.de/en/download/qsbar39.zip" rel="nofollow">http://www.qsbarcode.de/en/download/qsbar39.zip</a>). The dll will decode a bitmap image that contain barcode code39 into a string.</p> <p>In their example there are only VB and C example, but I need to use it in Delphi. here is the official example code in C:</p> <pre><code>#include &lt;windows.h&gt; #include &lt;stdio.h&gt; typedef int (WINAPI * CODE39_PROC)(char *, char *); int main(int argc, char* argv[]) { HINSTANCE hinstLib; CODE39_PROC ProcAdd; BOOL fFreeResult; char cFileName[512] = "\0"; char cResult[512] = "\0"; int iReturn = 0; if(argc &lt; 2) return 0; //no bitmap filename in argv[1] strcpy(cFileName,argv[1]); hinstLib = LoadLibrary("qsBar39"); if (hinstLib == NULL) return -1; //can't load lib ProcAdd = (CODE39_PROC) GetProcAddress(hinstLib, "ReadCode39"); if (NULL == ProcAdd) return -1; //can't access Proc //dll Proc call iReturn = (ProcAdd) (cFileName, cResult); printf("%s", cResult); fFreeResult = FreeLibrary(hinstLib); return iReturn; } </code></pre> <p>and this is what I try to code in Delphi</p> <pre><code>unit uRead; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, Mask, JvExMask, JvToolEdit; type TDLLFunc = function(namafile: PChar; hasil:PChar):integer; TForm2 = class(TForm) JvFilenameEdit1: TJvFilenameEdit; Edit1: TEdit; Button1: TButton; procedure Button1Click(Sender: TObject); private { Private declarations } public { Public declarations } end; const DLLFunc: TDLLFunc = nil; var Form2: TForm2; DLLHandle: THandle; implementation {$R *.dfm} procedure TForm2.Button1Click(Sender: TObject); var feedback : integer; hasil:PChar; begin DLLHandle := LoadLibrary('qsBar39.dll'); if (DLLHandle &lt; HINSTANCE_ERROR) then raise Exception.Create('library can not be loaded or not found. ' + SysErrorMessage(GetLastError)); try { load an address of required procedure} @DLLFunc := GetProcAddress(DLLHandle, 'ReadCode39'); {if procedure is found in the dll} if Assigned(DLLFunc) then feedback := DLLFunc(PChar(JvFilenameEdit1.Text), PChar(hasil)); showmessage(hasil); finally {unload a library} FreeLibrary(DLLHandle); end; end; end. </code></pre> <p>When I execute this code and debug, hasil only contains <strong>#$11'½</strong> while it should return some character in the barcode image (you can get the file image in the zip file). Please help me, thank you.</p> <hr> <p>latest update:</p> <p>@500, thanks, I have put stdcall </p> <p>@dthorpe, thanks, done</p> <p>Actually the advice is great, my code is supposed to running well, but I've mistakenly put JvFilenameEdit1.text instead of JvFilenameEdit1.FileName, my bad :)</p> <p>Thank you again for the advice, so here is the working code:</p> <pre><code>unit uRead; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, Mask, JvExMask, JvToolEdit; type TDLLFunc = function(namafile: PAnsiChar; hasil:PAnsiChar):integer; stdcall; TForm2 = class(TForm) JvFilenameEdit1: TJvFilenameEdit; Edit1: TEdit; Button1: TButton; procedure Button1Click(Sender: TObject); private { Private declarations } public { Public declarations } end; const DLLFunc: TDLLFunc = nil; var Form2: TForm2; DLLHandle: THandle; implementation {$R *.dfm} procedure TForm2.Button1Click(Sender: TObject); var feedback : integer; hasil: array [0..512] of char; begin DLLHandle := LoadLibrary('qsBar39.dll'); if (DLLHandle &lt; HINSTANCE_ERROR) then raise Exception.Create('library can not be loaded or not found. ' + SysErrorMessage(GetLastError)); try { load an address of required procedure} @DLLFunc := GetProcAddress(DLLHandle, 'ReadCode39'); {if procedure is found in the dll} if Assigned(DLLFunc) then feedback := DLLFunc(PAnsiChar(JvFilenameEdit1.FileName), @hasil); edit1.Text := StrPas(@hasil); finally {unload a library} FreeLibrary(DLLHandle); end; end; end. </code></pre>
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    1. COif you're using delphi 2009+(unicode version) then I think you need to replace PChar with PAnsiChar in Delphi code
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    2. COhi Dorin, i'm using Delphi 2006, but i tried to use PAnsiChar, thanks
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    3. COErwan: Don't change the title to (solved). Mark the question as answered.
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