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IEEE_TO_HOST

IEEE_TO_HOST

Name


    IEEE_TO_HOST

Purpose


    Translate an IDL variable from IEEE-754 to host representation

Explanation


    The variable is translated from IEEE-754 ("big-endian" as used, for
    example, in FITS data ), into the host machine architecture.
    Duplicates most of the functionality of the SWAP_ENDIAN_INPLACE procedure
    introduced in V5.6, with the addition of the IDLTYPE keyword.

Calling Sequence


    IEEE_TO_HOST, data, [ IDLTYPE = , ]
  INPUT-OUTPUT PARAMETERS:
    data - any IDL variable, scalar or vector. It will be modified by
            IEEE_TO_HOST to convert from IEEE to host representation. Byte
            and string variables are returned by IEEE_TO_HOST unchanged

Optional Keyword Inputs


    IDLTYPE - scalar integer (1-15) specifying the IDL datatype according
              to the code given by the SIZE function. This keyword
              is usually when DATA is a byte array to be interpreted as
              another datatype (e.g. FLOAT).

Example


      A 2880 byte array (named FITARR) from a FITS record is to be
      interpreted as floating and converted to the host representaton:
      IDL> IEEE_TO_HOST, fitarr, IDLTYPE = 4

Method


      The BYTEORDER procedure is called with the appropriate keyword

Modification History


      Written, W. Landsman Hughes/STX May, 1992
      Under VMS check for IEEE -0.0 values January 1998
      VMS now handle -0.0 values under IDL V5.1 July 1998
      Added new integer datatypes C. Markwardt/W. Landsman July 2000
      Post-V5.1 version, no VMS negative zero check W. Landsman July 2001
      Use size(/type) W. Landsman December 2002
      Use /SWAP_IF_LITTLE_ENDIAN keyword for 64bit types W. Landsman Feb 2003
      Do not use XDR keywords to BYTEORDER for much improved speed
                              W. Landsman April 2006
      Update cosmetic typo for structures W. Landsman October 2006



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