Send an array to a dll

BlitzMax Forums/BlitzMax Programming/Send an array to a dll

ftbass

(Posted 2006) [#1]

Hi,
I'm trying to send an array to a dll, but I can't send it. My application crashes.

the function in my dll is (written in C):

void ModifieTableau (int ptr[10])
{
   int i;
   for (i=0; i<10; i++)
   {
      ptr[i] = 15;
   }
}

the code in BlitzMax is:

Const DllName:String = "dllTest.dll"
Local DllHandle = LoadLibraryA(DllName)

If DLLhandle = 0 Then
   Notify "Unable to initialize dllTest.dll"
   End
EndIf

Global HelloWorld()"Win32" = GetProcAddress(DllHandle,"HelloWorld")
Global EnvoieValeur:Int(a:Int)"Win32" = GetProcAddress(DllHandle,"EnvoieValeur")
Global ModifieTableau(tab:Int Ptr)"Win32" = GetProcAddress(DllHandle,"ModifieTableau")

Local tableau:Int[10]
Local tab_ptr:Int Ptr
tab_ptr = Varptr tableau[0]

For i = 0 To 9
   tableau[i] = 5
Next

For i = 0 To 9
   Print(tableau[i])
Next

ModifieTableau(tab_ptr)     ' Application cashes here "Unhandled exception: Attempt to call uninitialize function pointer"

For i = 0 To 9
   Print(tableau[i])
Next

Could anyone help me ?

Dreamora

(Posted 2006) [#2]

Copy everything from the array to a TBank and send that.

Array is no plain array like in C where it is a continous memory block so you can't send it to C apps.

ftbass

(Posted 2006) [#3]

thanks for your reply :)

After a few tries, here are my modifications:

void ModifieTableau (int* ptr)
{
   int i;
   for (i=0; i<10; i++)
   {
      ptr[i] = 15;
   }
}

for the dll

Const DllName:String = "dllTest.dll"
Local DllHandle = LoadLibraryA(DllName)

If DLLhandle = 0 Then
	Notify "Unable to initialize dllTest.dll"
	End
EndIf


Global EnvoieValeur:Int(a:Int)"Win32" = GetProcAddress(DllHandle,"EnvoieValeur")
Global ModifieTableau(tab:Byte Ptr)"Win32" = GetProcAddress(DllHandle,"ModifieTableau")

Local i:Int
Local bank_ptr:Byte Ptr

Local MaBank:Tbank = CreateBank(10 * SizeOf(i))

bank_ptr = BankBuf(MaBank)

For i = 0 To 9
   PokeInt(MaBank, i*SizeOf(i), 10)
Next

For i = 0 To 9
   Print(PeekInt(MaBank, i*SizeOf(i)))
Next

ModifieTableau(bank_ptr)

For i = 0 To 9
   Print(PeekInt(MaBank, i*SizeOf(i)))
Next

in BlitzMax.

The different types between BlitzMax and C is quite confusing for me :/

Thanks again :)

Chris C

(Posted 2006) [#4]

wheres EnvoieValeur at least meet us half way!!

ftbass

(Posted 2006) [#5]

EnvoieValeur is a very simple function. I have no problem with it.

My problem was about sending an array to a dll.
It works with a bank, with the previous code, so I'll do like that.

Thanks :)

Chris C

(Posted 2006) [#6]

yeah but without it no one can run code, see where it fails, fix it, and help you out...

skidracer

(Posted 2006) [#7]

Ignore the bank comment and concentrate on the error "Attempt to call uninitialized function pointer".

I'd guess this means GetProcAddress(DllHandle,"ModifieTableau") is failing and returning null.

I would double check your spelling and make sure you are using c and not c++ (.c not .cpp file) for your dll else you will need to declare your function as extern "C" to stop it's name being mangled by the c++ compiler.