>  Docs Center  >  Libraries  >  Markwardt  >  FXGREAD

FXGREAD

FXGREAD

Name


  FXGREAD

Author


  Craig B. Markwardt, NASA/GSFC Code 662, Greenbelt, MD 20770
  craigm@lheamail.gsfc.nasa.gov
  UPDATED VERSIONs can be found on my WEB PAGE:
      http://cow.physics.wisc.edu/~craigm/idl/idl.html

Purpose


  Perform an unformatted read on a generic resource.

Major Topics


  File I/O, Pipes, URLs, FITS

Calling Sequence


  FXGREAD, UNIT, BUFFER, TRANSFER_COUNT=TC

Description



  FXGREAD performs an unformatted read on the unit UNIT. The UNIT
  must have previously been opened by FXGOPEN.
  Currently only unformatted reads are permitted because the precise
  number of bytes to read must be known ahead of time.
  In other respects, this procedure is similar to the READU built-in
  IDL procedure.
  You must use the specialized 'FXG' style functions to read, write
  and seek on file units opened with FXGOPEN:
    FXGOPEN - open resource
    FXGCLOSE - close resource
    FXGREAD - read from resource
    FXGWRITE - write to resource
    FXGSEEK - seek on resource (i.e., perform POINT_LUN)
    FXGFILTERED - determine if resource is a normal file.

Inputs



  UNIT - the unit number to operate on. The unit must have been
          previously opened by FXGOPEN.
  BUFFER - an array of the desired type and size is passed upon
            input to FXGREAD. Only basic types are permitted. Upon
            output, the array will have been filled with data from
            the resource. The full extent of the transfer can be
            determined by examining the TRANSFER_COUNT.

Keyword Parameters



  TRANSFER_COUNT - upon output, contains the number of elements
                    transferred to BUFFER.

Modification History


  Written, 1999, CM
  Documented, 02 Oct 1999, CM
  Changed copyright notice, 21 Sep 2000, CM
  $Id: fxgread.pro,v 1.3 2007/09/01 23:03:23 craigm Exp $



© 2019 Harris Geospatial Solutions, Inc. |  Legal
My Account    |    Store    |    Contact Us