undeclared identifier. for C-mex S-function.

I understand that this is a very common problem that a lot is facing. however I don't understand how to link to my program. It's a simple c = a+b program. I have the following as my C-Mex S-function:

#define S_FUNCTION_NAME Addition

#define S_FUNCTION_LEVEL 2

#include "simstruc.h"

static void mdlInitializeSizes(SimStruct *S) {

    int_T nInputPorts = 2; /* Set no. of input ports */
    int_T nOutputPorts = 1; /* Set no. of output ports */
    int_T needsInput = 1; /* Direct feed through = yes */

    int_T inputPortIdx = 0;
    int_T outputPortIdx = 0;

    ssSetNumSFcnParams(S, 0);
    if (ssGetNumSFcnParams(S) != ssGetSFcnParamsCount(S))
    {
        return; /* If no. of expected input parameters is not equal to no.
                   of parameters entered in dialog box, return. Simulink
                   to generate an error indicating parameter mismatched */
    }

    /* Configure input ports */
    if (!ssSetNumInputPorts(S, 2)) return;

    /* Configure first input ports */
    ssSetInputPortWidth(S, 0, DYNAMICALLY_SIZED); /* Set dimensions of first input port */
    ssSetInputPortDirectFeedThrough(S, 0, 1); /* Set direct feed through */

    /* Configure second input ports */
    ssSetInputPortWidth(S, 1, DYNAMICALLY_SIZED); /* Set dimensions of second input port */
    ssSetInputPortDirectFeedThrough(S, 1, 1); /* Set direct feed through */

    /* Configure output ports */
    if (!ssSetNumOutputPorts(S,1)) return;
    ssSetOutputPortWidth(S, 0, DYNAMICALLY_SIZED); /* Set dimensions of output ports */

    ssSetNumSampleTimes(S, 1); /* Set no. of sample times */

    ssSetSimStateCompliance(S, USE_DEFAULT_SIM_STATE);

    ssSetOptions (S,0);

} /* End of mdlInitializeSizes */

static void mdlInitializeSampleTimes (SimStruc *S)

{

    ssSetSampleTimes(S, 0, INHERITED_SAMPLE_TIME);
    /* Inherited Sample time: S-function block executes whenever driving block executes */
    ssSetOffsetTime(S, 0, 0.0); /* No offset required */
    ssSetModelReferenceSampleTimeDefaultInheritance(S); /* */
} /* End of mdlInitializeSampleTime */

static void mdlOutputs (SimStruc *S, int_T tid) {

    int_T i;
    InputRealPtrsType uPtrs = ssGetInputPortRealSignalPtrs(S,0);
    real_T *y = ssGetOutputPortRealSignal(S,0);
    int_T width = ssGetOutputPortWidth(S,0);

    for (i=0; i<width; i++) /* i = location of memory. from 0 to 1. */
    {
        *y++ = (*uPtrs[i+1]) + (*uPtrs[i]); /* c = a + b */
    }
} /* End of mdlOutputs */

static void mdlTerminate(SimStruct *S)

{

     /* No task to be perform at end of simulation therefore no termination required.
       But this is a compulsory function to have for C-mex S-function */
} /* End of mdlTerminate */
_
#ifdef MATLAB_MEX_FILE
#include "simulink.c"
#else
#include "cg_sfun.h"
#endif_

however when compiling on matlab, i keep getting the following error:

Addition.c:47: error: expected ‘)’ before ‘*’ token Addition.c:56: error: expected ‘)’ before ‘*’ token In file included from Addition.c:82: /DIST/it/sw/amd64/matlab/r2010b/simulink/include/simulink.c: In function ‘_ProcessMexSfunctionCmdLineCall’: /DIST/it/sw/amd64/matlab/r2010b/simulink/include/simulink.c:2545: error: ‘mdlInitializeSampleTimes’ undeclared (first use in this function) /DIST/it/sw/amd64/matlab/r2010b/simulink/include/simulink.c:2545: error: (Each undeclared identifier is reported only once /DIST/it/sw/amd64/matlab/r2010b/simulink/include/simulink.c:2545: error: for each function it appears in.) /DIST/it/sw/amd64/matlab/r2010b/simulink/include/simulink.c:2601: error: ‘mdlOutputs’ undeclared (first use in this function)

Any comments will be greatly appreciated!