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XSLPsetcbmessageF

Purpose

Set a user callback to be called whenever Xpress-SLP outputs a line of text

Synopsis

int XPRS_CC XSLPsetcbmessageF(XSLPprob Prob, void (XPRS_CC *UserFunc)
               (XSLPprob myProb, void *myObject, char *msg, int *len, int *msgtype), 
               void *Object);

Arguments

Prob  

The current SLP problem.

UserFunc  

The function to be called whenever Xpress-SLP outputs a line of text. UserFunc does not return a value.

myProb  

The problem passed to the callback function.

myObject  

The user-defined object passed as Object to XSLPsetcbmessage.

msg

Character buffer holding the string to be output.

len

Address of an integer holding the length in characters of msg excluding the null terminator.

msgtype  

Address of an integer holding the type of message. The following are system-defined:

1	Information message
3	Warning message
4	Error message

A negative value indicates that the Optimizer is about to finish and any buffers should be flushed at this time.

User-defined values are also possible for msgtype which can be passed using XSLPprintmsg

Object  

Address of a user-defined object, which can be used for any purpose by the function. Object is passed to UserFunc as myObject.

Example

The following example creates a log file into which all messages are placed. System messages are also printed on standard output:

FILE *logfile;
logfile = fopen("myLog","w");
XSLPsetcbmessage(Prob, CBMessage, logfile);

A suitable callback function could resemble the following:

void XPRS_CC CBMessage(XSLPprob Prob, void *Obj, 
                       char *msg, int *plen, int *pmsgtype) {
  FILE *logfile;
  int len, msgtype;
  logfile = (FILE *) Obj;
  len = *plen;
  msgtype = *pmsgtype;
  if (msgtype < 0) {
    fflush(stdout);
    if (logfile) fflush(logfile);
    return;
  }
  switch (msgtype) {
    case 1: /* information */
    case 3: /* warning */
    case 4: /* error */
      printf("%s\n",msg);
    default: /* user */
      if (logfile)
        fprintf(logfile,"%s\n",msg);
      break;
  }
  return;
}

Further information

If a user message callback is defined then screen output is automatically disabled.

Output can be directed into a log file by using XSLPsetlogfile.

Visual Basic users must use XSLPtoVBString or an equivalent to convert msg into a VB-type string.

XSLPsetcbmessageF is identical to XSLPsetcbmessage except that the callback function receives the message length and type by reference rather than by value.