Howto use DLL's?

Is there any good documentation available on how to use DLL's in Blitzmax where everything is explained step by step?

I want to use the Qlib32 library from www.quancom.com to send data to my USB relais interface.
I know which functions I need to use from the DLL and the values I need to send to them to control it, but I'm not sure where to start in Blitzmax so that I am able to send/receive data from this DLL.

The functions of this library I need are :

QAPIExtOpenCard(cardid, devnum) <= cardhandle
QAPIExtCloseCard(cardhandle)
QAPIExtWriteDo32(cardhandle, channel, value, mode)

The reason I want to use this is because of an Arcade project, I want to control the Leds and coin mechanism from within the games itself which I want to write for it.

If someone could help me a bit or send me in the right direction I would be greatfull.

If you don't have a lib file you can still use the DLL by the LoadLibrary API

There is a Qlib32.LIB available also.

And there are also loads of examples available for Visual basic and Delphi.

But in Blitzmax I don't know how the code should look like. The examples which I could find on this forum where a bit confusing for me...

I'm not sure if this is the correct way to start, but this is what I made so far :

dll = LoadlibraryA ("qlib32")

Global QAPIExtOpenCard:Long(cardid:Long, devnum:Long) = GetProcAddress(dll, "QAPIExtOpenCard")
Global QAPIExtWriteDo32:Long(cardhandle:Long, channel:Long, value:Long, mode:Long) = GetProcAddress(dll, "QAPIExtWriteDo32Card")
Global QAPIExtCloseCard:Long(cardhandle:Long) = GetProcAddress(dll, "QAPIExtCloseCard")

If this is correct I can go one step further...

Woohoo!, found it.... I needed Int instead of Long.
I tried the following code and the dll gave me back the results.

Global QAPIExtOpenCard (cardid:Int, devnum:Int) "win32"
Global QAPIExtCloseCard (cardhandle:Int) "win32"
Global QAPIExtWriteDO32 (cardhandle:Int, channel:Int, value:Int, mode:Int) "win32"
Global QAPIExtNumOfCards ()

dll = LoadlibraryA ("qlib32")

If dll=Null
 Print "Dammit"
 End
EndIf

QAPIExtNumOfCards = GetProcAddress(dll, "QAPIExtNumOfCards")
QAPIExtOpenCard = GetProcAddress(dll, "QAPIExtOpenCard")
QAPIExtWriteDO32 = GetProcAddress(dll, "QAPIExtWriteDO32")
QAPIExtCloseCard = GetProcAddress(dll, "QAPIExtCloseCard")


Local handle:Int = QAPIExtOpenCard(67,1)

Print handle
Print QAPIExtNumOfCards()

I only need to test it with my relais card connected when I get home. But I'm glad I know how to work with dll's now... took me some days

Here is the final code which I can include in all my projects which must use the relais interface card.

' Relaishandler v1.0 for Quancom USBREL8LC USB Relais interface

' Written by Mark Gerritsen

' Use :

' relais (x, x, x, x, x, x, x, x) to activate relais
' x can be either 1 or 0 and each x handles 1 relais


' Load Quancoms Qlib library 
dll = LoadlibraryA ("qlib32")

If dll=Null
 RuntimeError "Unable to load library"
 End
EndIf

Global QAPIExtOpenCard:Int (cardid:Int, devnum:Int) "win32"
Global QAPIExtCloseCard (cardhandle:Int) "win32"
Global QAPIExtWriteDO32 (cardhandle:Int, channel:Int, value:Int, mode:Int) "win32"
Global handle:Int

QAPIExtNumOfCards = GetProcAddress(dll, "QAPIExtNumOfCards")
QAPIExtOpenCard = GetProcAddress(dll, "QAPIExtOpenCard")
QAPIExtWriteDO32 = GetProcAddress(dll, "QAPIExtWriteDO32")
QAPIExtCloseCard = GetProcAddress(dll, "QAPIExtCloseCard")

Local cardnumber:Int = 0

While handle = 0
If cardnumber > 8
RuntimeError "Unable find card"
  End
EndIf
handle = QAPIExtOpenCard(67,cardnumber)
cardnumber = cardnumber + 1
Wend

' Reset Relais interface
relais(0,0,0,0,0,0,0,0)

Function relais(out1:Int,out2:Int,out3:Int,out4:Int,out5:Int,out6:Int,out7:Int,out8:Int)
Local value = 0
If out1 = 1 Then value = value + 1
If out2 = 1 Then value = value + 2
If out3 = 1 Then value = value + 4
If out4 = 1 Then value = value + 8
If out5 = 1 Then value = value + 16
If out6 = 1 Then value = value + 32
If out7 = 1 Then value = value + 64
If out8 = 1 Then value = value + 128
Print value
QAPIExtWriteDO32(handle,0,value,0)
QAPIExtCloseCard(handle)
End Function

Now I can use an easy function to activate all relais using relais(1,1,1,1,1,1,1,1) or relais(0,0,0,0,0,0,0,0) to disable them all, or any other combination.

Now I can continue with my arcade project :-)

Hi Mark,

I was trying the same as you but couldn't get it to work. You seem to have the ID 67 in this line:

handle = QAPIExtOpenCard(67,cardnumber)

I do get it to work with such a device, but with numer 64... how can we let the program choose the right ID by itself?