dll function problem (please)

[gustavoAUDACES]

Hello,

I have a question about calling function DLLs and the SF7.
Follow, i have a example function wich store in the variable test the value "shark"(string).

Call of DLL function in the SF7.

Local String arg1= "Select the computer server";
Local String computerName= "0";

DLLResult= DLL.CallFunction(compnet.dll, "NameOfComputerServer", "arg1,computerName", DLL_RETURN_TYPE_LONG, DLL_CALL_STDCALL);

Follow, i show you the source code of the DLL function.

void NameOfComputerServer(char *msg,char *&test)
{
ShowMessage(msg);
test= new char[6];
strcpy(test,"Shark");
ShowMessage(test);
}

That´s function return by reference one value for the variable test.
I need get that´s value.
I can´t bring this value for to SF7. How am i make this????
If do you have any example for this case please send me.

Thank you!!

Gustavo Pasqualini

[Brett]

You cannot return values as string references. That is, string pointers are one-way (in). You could do the following instead:

C code:

char szReturn[6];

char* NameOfComputerServer(char *msg)
{
ShowMessage(msg);
strcpy(szReturn,"Shark");
ShowMessage(szReturn);
return szReturn;
}

SUF code:

local larg1= "Select the computer server";
local computerName= "0";

DLLResult= DLL.CallFunction(compnet.dll, "NameOfComputerServer", "\""..larg1..",\""..computerName.."\"", DLL_RETURN_TYPE_STRING, DLL_CALL_STDCALL);

[gustavoAUDACES]

Follow, i show you my code in SF7.
It´s not work, an error appear...

What is my mistake???

local titu= "TITLE";
local msg= "Select Server Name";
local aguar= "Wait...";
local String ComputerName= "0"

DLLResult= DLL.CallFunction(SessionVar.Expand("%TempLaunchFol der%\\compnet.dll"), "_SelectServerName", "\""..titu..",\""..msg..",\""..aguar..",\""..Compu terName.."\"", DLL_RETURN_TYPE_LONG, DLL_CALL_STDCALL);

[Worm]

DLLResult= DLL.CallFunction(SessionVar.Expand("%TempLaunchFol der%\\compnet.dll"), "_SelectServerName", "\""..titu.."\",\""..msg.."\",\""..aguar.."\",\""..Compu terName.."\"", DLL_RETURN_TYPE_LONG, DLL_CALL_STDCALL);

[Brett]

I think Worm hit it there. I was missing some quotes...

[gustavoAUDACES]

We make an update in a function in our DLL, and remove the reference variable.
Now, the DLL return the wanted value. We try to use that new DLL in a WISE Solution. In that software, the new DLL is running correctly.
After we try to use the new DLL in your program it isn't running.
I don't know what's happenning. Do you have a tip for us?
The buy of a licence depends on that DLL running on our setup.

Thank's a lot!

[Worm]

Just looking at it again... change the return vallue to a string instead of a long.

[gustavoAUDACES]

I have change the return value of that DLL to String and nothing...

The DLL function it´s look like the fucntion below:

char *NameOfComputerServer(char*arg1,char*arg2,char*arg 3)
{
char test[500];
strcpy(test,"SHARK");
return test;
}

The code in SF7:

local String titu= "Audaces Vestuário";
local String msg= "Escolha nome do micro servidor";
local String aguar= "Aguarde...";
local String te= "namePC";

te= DLL.CallFunction(SessionVar.Expand("%TempLaunchFol der%\\CompNet.dll"), "_NameOfComputerServer", "\""..titu.."\",\""..msg.."\",\""..aguar.."\"" , DLL_RETURN_TYPE_LONG, DLL_CALL_STDCALL);

Dialog.Message("TITLE",te,MB_OK);

[gustavoAUDACES]

The Return Of That Dll Is A String Value...

[Brett]

Have you tried changing DLL_CALL_STDCALL to DLL_CALL_CDECL? Also, try returning a global char* instead of the local one. The local one probably goes out of scope right after it is returned:

char test[500];

char *NameOfComputerServer(char*arg1,char*arg2,char*arg 3)
{
strcpy(test,"SHARK");
return test;
}

Also, you are using "_NameOfComputerServer" instead of "NameOfComputerServer" as the function name. Why is that? Try compiling the DLL in such a way that it does not decorate the function names.

Read this article for an example of how to make a compatible DLL:

How to Create a Simple Win32 DLL

[gustavoAUDACES]

Hello,

I will explain how the fuctions work.
We have a function wich return the name of the computer and other wich show one window, where the user selects one name of the network computers .

The first function works more or less then:

char *returnNamePC()
{
char namePC[500];
//take the name of the PC
strcpy(namePC,GetLocalNamePC());

return namePC;
}
This function don´t have parameters and work correctly in the SF7.

The another function, have tree parameters:

char *nameOfComputerServer(char *titleScreen,char *msg1,char *msg2)
{
char namePC[500];
//call the screen for the user select the server name
strcpy(namePC,ChooseNameOfPC(titleScreen,msg1,msg2 ));

return namePC;
}

The functions works of the same form, but when i call the first function (in SF7), anything is ok. But when i call the second fuction the return (in SF7) is zero.
We make a test, with a new fuction without parameters:

char *nameOfComputerServer()
{
char namePC[500];

//call the screen for the user select the server name
strcpy(namePC,ChooseNameOfPC("titleScreen","msg1", "msg2"));

return namePC;
}

This new fuction returns 0 too. Can you do explain me why???
Apparently all is correct.

Thank's...