Convert a MEX-function to an S-function

Dear all,

I want to implement an opensource nonlinear solver in Simulink such that it is suitable for code-generation (XPC-target). For this I want to convert an existing .mex file into an S-function.

Some background info:

I am using the IPOPT nonlinear solver which is supplied with the OptiToolbox (opensource) compliled as a precompiled .mex file which works perfectly under Matlab. However, to be able to use the solver in XPC-target I need to create and S-function block in Simulink.

Other options I've tried so far:

• Since I already have a mex-file I thought it would be convenient to use that inside a simple 'Matlab Function'-block. This works in Simulink, but the code generator cannot compile the Simulink diagram to a real-time executable code.
• Creating an S-function in which I call the .mex function. This code cannot be compiled since the .tlc file is missing.

Question

After some search on fora and Matlab central, I found out that I should create a C MEX S-function and compile it. To make life easier, Simulink comes with an S-function builder in which libraries, headers etc. can be added. I failed in constructing one and it is driving me crazy.

I think it would be easiest to convert the .mex function into an S-function (if possible). My question to you therefor is:

Who has experience in converting an .mex function (based on a large set of C++ routines) into an S-function in Simulink

Your help will be greatly appreciated!