mexPrintf() not working from within mdlStart method of C Mex S-Function

Hi There,

I'm trying to perform some debugging with a C MEX S-Function in Simulink but both mexPrintf() and ssPrintf() do not print anything to either the command window or the diagnostic viewer when called within the mdlStart method. Both mexPrintf() & ssPrintf() work within the mdlOutputs() & mdlTerminate() methods. Is there another function I should be using to print custom debugging messages from within the mdlStart() method?

static void mdlStart(SimStruct *S)
{
    //Both of these following lines fail to print to either command window or diagnostic viewer
    mexPrintf("Test test");
    ssPrintf("Test text");
}

[Yongjian Feng]

Can you use an external debuger instead? Use gdb or visual studio to attach to the matlab process, and then you can put a break point in this function.

[Chris Morley]

Sorry I'm not well versed with using vdp. Are you suggesting that I use gdp or visual studio to print my text or do you mean I use one of these tools to determine why the text is not printing?