# Enable or Disable Error Logging

You can enable or disable error logging using either the API or environment variables. By default, a file called `kvoop.log` is created in the system temporary directory; however, you can change the path and file name of this file (see Change the Path and File Name of the Log File).

## Use the API

To enable logging through the API, set the flag `FILTERFLAG_OOPLOGON` when you instantiate the Filter object:

    objFilter = new Filter(outputCharSet,
        FilterConstant.FilterFlagsConstant.FILTERFLAG_OOPLOGON,
        license);

To disable logging, set the flag `FILTERFLAG_OOPLOGOFF`.

## Use Environment Variables

To enable logging, add the environment variable `KVOOPLOGON`, and set the variable value to 1. To disable logging, do not set the environment variable `KVOOPLOGON`.

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