idlastro / Miscellaneous (Non-Astronomy) Procedures: IEEE_TO_HOST

[Source code]

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