Access Violation When Function Reaches END;

[Remy Lebeau]

isn't there Somewhere an Example to how to use ZAJsonRequestW ?

Try this:

Code: Pascal  [Select][+][-]

1. //Def
2. TZAJsonRequestW = function(sRequest : PWideChar): PWideChar; stdcall;
3.  
4. //Calling The DLL
5. Function Call_ZAJsonRequestW(const sRequest : UnicodeString): UnicodeString;
6. var
7.   // Legt eine passende Variable (Datenfeld) für das DLL-Unterprogramm an
8.   ZAJsonRequestW : TZAJsonRequestW;
9.   // Legt einen Handle für den Handle der DLL an
10.   LibHandle: THandle;
11. begin
12.   Result := '';
13.   //Einbinden Der DLL
14.   LibHandle := LoadLibrary(PChar('C:\DLLS\FANselect.dll'));
15.   if (LibHandle <> 0) then
16.   try
17.     // Weisst der Variablen ZAJsonRequestW die Adresse des Unterprogrammaufrufs zu
18.     // 'ZAJsonRequestW' aus der DLL FANSelect.dll zu.
19.     Pointer(ZAJsonRequestW) := GetProcAddress(LibHandle, 'ZAJsonRequestW');
20.  
21.     // Prüft, ob eine gültige Adresse zurück gegeben wurde
22.     if Assigned(ZAJsonRequestW) then begin
23.       //Blackbox aufrufen
24.       Result := ZAJsonRequestW(PWideChar(sRequest));
25.     end;
26.   finally
27.     FreeLibrary(LibHandle);
28.   end;
29. end;
30.  
31. //Calling in Code
32. //Both Strings Here are UnicodeStrings
33. JZaRueckgabe := DLLAufrufe.Call_ZAJsonRequestW(JZa);

Alternatively:

Code: Pascal  [Select][+][-]

1. //Def
2. TZAJsonRequestW = function(sRequest : PWideChar): PWideChar; stdcall;
3.  
4. //Calling The DLL
5. Function Call_ZAJsonRequestW(const sRequest : UTF8String): UTF8String;
6. var
7.   // Legt eine passende Variable (Datenfeld) für das DLL-Unterprogramm an
8.   ZAJsonRequestW : TZAJsonRequestW;
9.   // Legt einen Handle für den Handle der DLL an
10.   LibHandle: THandle;
11. begin
12.   Result := '';
13.   //Einbinden Der DLL
14.   LibHandle := LoadLibrary(PChar('C:\DLLS\FANselect.dll'));
15.   if (LibHandle <> 0) then
16.   try
17.     // Weisst der Variablen ZAJsonRequestW die Adresse des Unterprogrammaufrufs zu
18.     // 'ZAJsonRequestW' aus der DLL FANSelect.dll zu.
19.     Pointer(ZAJsonRequestW) := GetProcAddress(LibHandle, 'ZAJsonRequestW');
20.  
21.     // Prüft, ob eine gültige Adresse zurück gegeben wurde
22.     if Assigned(ZAJsonRequestW) then begin
23.       //Blackbox aufrufen
24.       Result := UTF8Encode(ZAJsonRequestW(PWideChar(UTF8Decode(sRequest))));
25.     end;
26.   finally
27.     FreeLibrary(LibHandle);
28.   end;
29. end;
30.  
31. //Calling in Code
32. //Both Strings Here are UTF8Strings
33. JZaRueckgabe := DLLAufrufe.Call_ZAJsonRequestW(JZa);

[Mr.Madguy]

Thanks Guys

It Did work with The Pointers. Not The Result i wanted but atleast i dont get AV Anymore.

Thanks again for ur effort and patience.

BSTR variant need extensive testing with asm debugger. But I don't have time to do it and don't want to mess with some libraries, I'm unfamiliar with. Sometimes only asm debugging can fix problem. For example one of hardest tasks for me was - to use 7z.so in my Lazarus project. It had taken so much time to realize, what kind of strings are used there.

[Weitentaaal]

Thanks Guys

It Did work with The Pointers. Not The Result i wanted but atleast i dont get AV Anymore.

Thanks again for ur effort and patience.

BSTR variant need extensive testing with asm debugger. But I don't have time to do it and don't want to mess with some libraries, I'm unfamiliar with. Sometimes only asm debugging can fix problem. For example one of hardest tasks for me was - to use 7z.so in my Lazarus project. It had taken so much time to realize, what kind of strings are used there.

100 % Agree on that... we never looked that detailed into "Strings" in Shool (finished Shool last year)... first expreience with Strings like that.