Hi, I’m trying to port some MATLAB code over to Julia that relies on some of MATLAB’s `calllib()`

functions. However, I am confused how I am supposed to get multiple outputs out of Julia’s `ccall()`

function as we are only able to define the type of a single output but are required to type all the inputs, so this tells me that this is not possible.

Here is an example of the issue. A MATLAB call looks like this:

```
libname = 'refprop';
T = 300.0;
P_rp = 101325;
z = 1;
herr = 32*ones(255);
[~,~,~,D_rp,Dl,Dv,x,y,q,e,h,s,cv,cp,w,ierr,errTxt] = calllib(libName,'TPFLSHdll', T, P_rp, z, 0, 0, 0, zeros(1,numComponents), zeros(1,numComponents), 0, 0, 0, 0, 0, 0, 0, 0, herr, 255);
```

In Julia, I do:

```
T = 300.0;
P_rp = 101325;
z = 1;
# herr = 32*ones(255); # for some reason passing this breaks everything, but that's another problem
D_rp = Cdouble;
Dl = Cdouble;
Dv = Cdouble;
val = ccall((:TPFLSHdll,:REFPRP64),Cdouble,(Cdouble,Cdouble,Cdouble,Cdouble,Cdouble,Cdouble,Ptr{Cdouble},Ptr{Cdouble}, Cdouble, Cdouble, Cdouble, Cdouble, Cdouble, Cdouble, Cdouble, Cdouble, Ptr{Cdouble}, Cdouble),T,P_rp,z,0,0,0,zeros(1),zeros(1),0,0,0,0,0,0,0,0,32*ones(255),255);
```

And this gives me `val = 0.0`

, and I don’t know how to access the variables such as `D_rp`

. Is this even possible in Julia or do I have to stay in MATLAB?

By the way, the documentation of the TPFLSHdll library with inputs and outputs (?) is on the bottom of document page 124 /pdf page 128 HERE.