Troubleshooting RtPlot

• When starting RtPlot, Windows notifies of a missing DBGHELP.DLL file.
  
  

  • The file DBGHELP.DLL is needed for RtPlot to create a small dump file if it crashes, to assist in finding the reason for the crash. In some distributions it was mistakenly not included. It can be downloaded from Microsoft web and probably from other sources on the web. The package on RtPlot web includes version 5.1.2600.0 of this file.

• File is updated, but the RtPlot display does not. This sometime happen because the OS does not always update the write time of the data file, even when after data was written. Most likely it happens when a single line of data is added at a time. If you are writing your own code, you can do one of the following:
  
  
  • Quick & dirty fix:

    Close and reopen the data file. Assuming that f is a file pointer (i.e. FILE *) and the file name is data.txt. After adding a line of data do:

    fclose(f);
    f = fopen("data.txt", "a"); /* Close and reopen in append mode */
    
    This normally forces the OS to update the write time of the file.
    
    

  • Call functions such as _utime(), _futime(). These functions are non-standard but VC++, MingW and other compilers has them.
    
    
  • Update the write time of the file using Windows API. You must first obtain a handle of your file (remember to include <windows.h> header file):

    HANDLE h = (HANDLE) (_get_osfhandle(_fileno(f) ) );
    
    After you write your data, flush the buffer:

    fflush(f);

    Then update the write time:
    
    FILETIME write_time;
    GetSystemTimeAsFileTime(&write_time_);
    SetFileTime(h, NULL, NULL, &write_time);
    
    That should do it.

  If you don't write the code which updates the data file, Version 0.62 introduced a new option which will force an update the display after a set number of checks in which the write-time of the file has not changed. This option is set in the bottom part of the Timer menu. See Sec. Usage in the documentation.

  Alternatively, you can try to use a port of the UNIX utility touch. Doing touch data.txt from the command prompt will update the write time of the data file "data.txt". You can create a batch file to update periodically the write time of "data.txt".

  For more information see Cooperating with RtPlot section of the documentation.

• Large CPU consumption on big data sets, especially when the mouse moves over the window area.
  
  

  • Try turning off Data tips by unchecking it in the contex menu. When Data tips is on, RtPlot needs to test if the cursor is near a data point, so that it knows to show the coordinates. This may consume too much CPU on very big files.