quadprog in a Matlab Simulnk Level 2 S function block

I have actually never used User Defined Blocks in Simulink, but for some time I have been trying to put my controller block which uses the quadprog() into a Simulink S function block .

I managed to use "coder.extrinsic()" function for incorporating quadprog() in a "Matlab Function Block" . But the same does not work in the a S function block .

Can anyone help me with this? Does the S Function block allow us to call another function in form of a code? If yes then how does that work?

My main objective is to convert a code that I wrote in Matlab to a Simulink S function block.

I am using Matlab R2013a .