Callbacks

It is good practice to set up at least a message callback, so that any messages produced by the system appear on the screen or in a file. The XSLPsetcbmessage function sets both the Xpress NonLinear and Xpress Optimizer callbacks, so that all messages appear in the same place.

void XPRS_CC XSLPMessage(XSLPprob my_prob, void *my_object, char *msg, int len,
       int msg_type)
{
  switch (msg_type) {
  case 4: /* error */
  case 3: /* warning */
  case 2: /* dialogue */
  case 1: /* information */
    printf("%s\n", msg);
    break;
  default: /* exiting */
    fflush(stdout);
    break;
  }
}

This is a simple callback routine, which prints any message to standard output.