# Generate an Error Log

You can monitor and debug filtering operations by enabling a detailed error log. This enables you to see errors that are generated at run time, and to track problem files in stream or file mode.

NOTE: Error logs are not generated when in-process filtering is enabled.

The error log might include the following information:

- Generated error codes.
- A time stamp.
- The path and file name of the file in which the error occurred.
- The length of the file in which the error occurred. If the name of the original file or the name of the temporary file are not obtained in stream mode, the file length is reported.

The following is a sample log file:

    -KVOOPE 12 # Time: 11:14:32 # File Len = 68140
    -KVOOPE 13 # Time: 11:23:05 # H:\files\WP\Word97\fnldmsa.doc
    -KVOOPE  5 # Time: 12:15:54 # H:\files\SS\XL2000\corporate.xsl
    -KVOOPE  5 # Time: 12:45:19 # H:\files\WP\WPerf5\wp501.doc
    -KVOOPE 12 # Time: 14:25:33 # H:\files\PG\PPoint95\95.ppt
    -KVOOPE 26 # Time: 16:26:04 # File Len = 19117568
    -KVOOPE 10 # Time: 20:27:40 # File Len = 19117568

You can specify the information that is written to the log file by using either the API or environment variables. To configure a log file for a single filtering session, use environment variables. To configure a log file for all filtering sessions, use the API. Configuring the log file by using the API overrides the same settings in the environment variables. You can also specify additional settings in the `formats.ini` file.

You can configure the following features of the log file:

- Enable or disable logging. See Enable or Disable Error Logging.
- Change the default path and file name of the log file. See Change the Path and File Name of the Log File.
- Include memory errors in the log file. See Report Memory Errors.
- Specify a memory guard that is used to generate memory overwrite errors in the log. See Specify a Memory Guard.
- Include the input file name in the log file when filtering a stream. See Report the File Name in Stream Mode.
- Include extended error codes that provide more detail on a general error (`KVERR_General`). See Report Extended Error Codes.
- Specify the maximum size of the log file. See Specify the Maximum Size of the Log File.

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