calling a dll

I wish to call my dll (simpledll)from Matlab R2007b; I have loaded the dll successfully. Then from the 'libfunctions' I get the function: "doublePtr changevar(double, doublePtr)" displayed. This looks ok to me, as all it does is inputs a value (double) & returns a value (double).

I tried calling it using the following: in1=2; [out1]=callib('simpledll','changevar',in1);

But I get the following error on the calling line: "Undefined function or method 'callib' for input arguments of type 'char'."

What does this mean; have I got the format for calling the dll wrong; what should I have put?

Answer 1

[Friedrich]

Hi,

this be because calllib is written with three l instead of two like you did.

[Steve]

Yes you are correct;MatLab did not highlight the typo error. I have corrected this but now get the error message "Error using==> calllib

No method with matching signature". Any ideas what this means?

[Kaustubha Govind]

doublePtr changevar(double, doublePtr)

this seems to indicate that the function needs two inputs, but you are only providing one.

Answer 2

[Steve]

Yes you are correct;MatLab did not highlight the typo error. I have corrected this but now get the error message "Error using==> calllib No method with matching signature". Any ideas what this means?

[Friedrich]

Your function changevar expects two inputs but you pass only one input which leads the error that no function with matching structure is found, since you dont have a function called changevar which expects one input.

[Steve]

The dll (simpledll)has a function called 'changevar' with one input 'in1' and one output 'out1'. So have I got the MatLab format wrong: [out1]= calllib('simpledll','changevar',in1)?

[Kaustubha Govind]

You said that libfunctions lists the function as "doublePtr changevar(double, doublePtr)" - this indicates that the function has 2 inputs. What is the corresponding signature for the function with one input?