;+
;
; @file_comments
; write an Oasis file (version < 2.5)
;
; @param FILENAME {in}{required}
; the filename
;
; @param VARNAME {in}{required}
; the name of the variable to be written
;
; @param Z2D {in}{required}
; the variable (2D array) to be written
;
; @keyword I2
; @keyword I4
; @keyword I8
; @keyword R4
; to change the default format (R8) of the data to be written.
;
; @keyword APPEND
; to open the file with the file pointer at the end of the file, ready for
; data to be appended.
;
; @restrictions
; varname is automatically written as a "character*8"
; by default z2d is written as an R8 array
;
; @history
; Sebastien Masson (smasson\@lodyc.jussieu.fr)
;                      July 01, 2002
; @version
; $Id$
;
;-
;
PRO write_oasis, filename, varname, z2d, I2 = i2, I4 = i4, I8 = i8, R4 = r4, APPEND = append
;
  compile_opt idl2, strictarrsubs
;
   openw, unit, filename , /F77_UNFORMATTED, /GET_LUN, /SWAP_IF_LITTLE_ENDIAN $
    , error=err, APPEND = append
   if err ne 0 then begin
      ras = report(!err_string)
      return
   endif

   writeu, unit, string(varname, format='(a8)')
   case 1 of
      keyword_set(i2):writeu, unit, fix(z2d)
      keyword_set(i4):writeu, unit, long(z2d)
      keyword_set(i8):writeu, unit, long64(z2d)
      keyword_set(r4):writeu, unit, float(z2d)
      ELSE:writeu, unit, double(z2d)
   endcase

   free_lun,unit
   return
end