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XSLPsetcbmessage

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Purpose

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

Synopsis

int XPRS_CC XSLPsetcbmessage(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	Length in characters of msg excluding the null terminator.
msgtype	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 len, int msgtype) {
  FILE *logfile;
  logfile = (FILE *) Obj;
  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.

When used with VB, the callback function has the prototype:

Public Sub mycbfunc (ByVal prob As Long, ByVal obj As Long, 
                     ByVal msg As Long, ByVal length As Long, 
                     ByVal msgtype As Long)

Related topics

XSLPsetcbmessageF, XSLPsetlogfile, XSLPtoVBString

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