GPDL $DEBUG
$DEBUG (debugFlags)
Return value: The old debug flags...so you can put things back the way they were.
Use the $DEBUG function to turn debug capabilities on/off.
Bit 0 = DBG_messageBox
Causes a Windows message box to appear when certain errors such as improper $GREP search strings are encountered at runtime.
Bit 1 = DBG_functionTrace
Causes a log message to be created in the GPDL log file whenever a user function is called or returns. This log entry records the parameters and return value.