Calling external DLL fails

[gyc]

I am trying to use an external DLL with LV.

This DLL is known to work with VB and C++; however, when I call it LV traps a low level memory corruption error and stops the VI.

What might be the problem - or what am I doing wrong?

Gyc

[i2dx]

maybe the wrong calling convention in the function prototype ?

maybe i can help, if you post the code and the function prototype ?

cheers,

cb

[gyc]

maybe the wrong calling convention in the function prototype ?

maybe i can help, if you post the code and the function prototype ?

cheers,

cb

5236[/snapback]

Here's the prototype:

int ADAMTCP_Connect(char szIP[],

unsigned short port,

int iConnectionTimeout,

int iSendTimeout,

int iReceiveTimeout);

Download File:post-2388-1120680769.vi

[i2dx]

the string input is the problem.

the help you need can be found here:

http://zone.ni.com/devzone/conceptd.nsf/we...6256869005ff2ed

good look

CB

[gyc]

the string input is the problem.

the help you need can be found here:

http://zone.ni.com/devzone/conceptd.nsf/we...6256869005ff2ed

good look

CB

5238[/snapback]

I tried to pass the string as "handle" and as "handle pointer" but it doesn't work: LV is just kicked out with absolutely no messages.

Thanks anyway!

Gyc

[Rolf Kalbermatter]

I tried to pass the string as "handle" and as "handle pointer" but it doesn't work: LV is just kicked out with absolutely no messages.

Thanks anyway!

Gyc

5239[/snapback]

That's because the DLL does NOT expect a LabVIEW handle or even a pointer to such. Instead it expects a pointer to a C string.

char somevar[]

is equivalent to

char *somevar

as far as the C compiler is concerned. This is definitely a C string pointer. Configure the Call Library Node parameter accordingly and you should be fine. A LabVIEW string handle or pointer to such can only ever be used for DLLs which have been explicitedly developed to be called by LabVIEW.

Rolf Kalbermatter