giriraj
24th October 2007 13:51 UTC

Passing string parameter to a dll (a plugin actually)
Hi .
I am trying to pass a string argument to a dll(plugin) and then trying to write the same to a text file.
This is declaration in the header file of my dll

DECLDIR void writeToFile(char *str);

and following is the function definition in a cpp file.

void __declspec(dllexport) writeToFile(TCHAR data[])
{
}
When i run it through the nsi file ;i get "An unhandled win32 exception in the application"

Kindly help me sort this out.
This is quite urgent.

Anders
24th October 2007 14:29 UTC

when you say plugin, do you mean NSIS plugin (if so, exported functions have a specific format, checkout the source for one of the plugins that ship with nsis)

if not, you must use the system plugin, something like:
system::call 'yourplugin::writeToFile(t "foo")'

(if your export is not stdcall(i would guess yours is cdecl), you must use the "?c" option (read the system readme))

giriraj
24th October 2007 14:35 UTC

Anders,
By dll i mean a sample NSIS plugin i created using Microsoft Visual C++ 2005.
I am just not able to pass the string to the dll i created.
Is there any way to access the string in my dll.
i tried collecting the string into a char * variable,but it didn't work.

Afrow UK
24th October 2007 14:50 UTC

When you say an NSIS plug-in, have you based it on exdll? You'd have to use popstring().

Stu

giriraj
24th October 2007 15:01 UTC

i don't understand by "based on exdll".
sorry for being a novice.
i made a dll using Microsoft Visual C++ 2005 dll creation wizard.
It contains a .h file and a .cpp file in place.
then i made a dll out of it.
i am able to make function calls which does not involve passing of parameters.
but i am not able to access a string that i pass to a LPWSTR variable or a char* variable.

Regards,
Giriraj

Joel
24th October 2007 19:12 UTC

To use dll as nsis plugins you need to get the exdll header and see the function creation protocal in order to use with nsis...Grab the nsis source code @ main page and look @ Contrib\exdll

kichik
24th October 2007 20:49 UTC

It's also available in Examples\Plugin when you install the NSIS package.

giriraj
30th October 2007 13:19 UTC

i had a look at the example in Examples\Plugin but i wasn't able to decipher it.
i followed the process as explained in the sample project in Examples\Plugin.
but i couldn't retrieve the parameter i passed.
I mean isn't there a simple way to pass a string to a dll and retrieve it.

Afrow UK
30th October 2007 13:28 UTC

Yes like I said, in NSIS use MyPlugin::Function "hello" then in the plug-in use:

char *param = (char*)LocalAlloc(LPTR, string_size);
popstring(param);
...
// param == "hello"
LocalFree(param);

Stu