DCMTK Version 3.7.0 OFFIS DICOM Toolkit

envvars.txt file

    ===========================
    DCMTK ENVIRONMENT VARIABLES
    ===========================

    The behavior of the DCMTK tools and libraries can be modified by a
    number of runtime environment variables which are explained below.

    DCMDICTPATH
      Affected: dcmdata
      Explanation: On Unix platforms, all DCMTK applications load a DICOM data
        dictionary from file upon startup.  By default, the file /usr/local/share/
        dcmtk-<VERSION>/dicom.dic will be loaded.  If the DCMDICTPATH environment
        variable is set, the applications will attempt to load DICOM data
        dictionaries specified in the DCMDICTPATH environment variable instead.
        The DCMDICTPATH environment variable has the same format as the shell PATH
        variable in that a colon (":") separates entries.  The data dictionary code
        will attempt to load each file specified in the DCMDICTPATH environment
        variable.  It is an error if no data dictionary can be loaded.
            On Win32 platforms, a built-in dictionary is used by default.  If the
        DCMDICTPATH environment variable is set, the applications will attempt to
        load _additional_ DICOM data dictionaries specified in the DCMDICTPATH
        environment variable instead. The DCMDICTPATH environment variable has the
        same format as the shell PATH variable in that a semicolon (";") separates
        entries.  The data dictionary code will attempt to load each file specified
        in the DCMDICTPATH environment variable.

        See also: documentation in dcmdata/docs/datadict.txt or
                  /usr/local/share/doc/dcmtk-<VERSION>/datadict.txt.

    DCMICONVPATH
      Affected: oficonv
      Explanation: The oficonv library uses a set of data files containing encoding
        scheme database and character set mapping data.  By default, the files are
        expected in the "esdb" and "csmapper" subdirectories of the
        DEFAULT_SUPPORT_DATA_DIR directory.  This environment variable can be used
        to specify a different data directory containing the "esdb" and "csmapper"
        subdirectories.

    TCP_BUFFER_LENGTH
      Affected: dcmnet
      Explanation: By default, DCMTK does not modify the TCP send and receive buffer
        length, i.e. the operating system is responsible for selecting appropriate
        values.  If the environment variable TCP_BUFFER_LENGTH is set, it specifies
        an override for the TCP buffer length. The value is specified in bytes, not
        in Kbytes.  If set to 0, a buffer length of 64K, which was the default value
        for previous versions of the DCMTK, is used.

    TCP_NODELAY
      Affected: dcmnet
      Explanation: If this environment variable is set and contains a non-zero
        number (e.g. "1"), the Nagle algorithm will be disabled for TCP transport
        connections, which might result in better network performance on some
        systems/environments, especially when many small network packets are to
        be sent.  If it is set and contains the number "0", the Nagle algorithm
        will not be disabled.  If the environment variable TCP_NODELAY is not set,
        the default behavior applies (see compiler macro DISABLE_NAGLE_ALGORITHM
        in config/docs/macros.txt or /usr/local/share/doc/dcmtk-<VERSION>/
        macros.txt).

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