PRO safe_fits_write, dir, file, maxtry, data, header, status

; Description: This module writes out a FITS image file, along with its header.
;              The module first checks that the target directory is available 
;              on disk before writing. If the directory is not available, 
;              then the module waits 1 second before trying again. The module 
;              will attempt to write out the image data a total of "maxtry" times
;              before giving up and returning a status of zero.
;
; Input Parameters:
;
;   dir - STRING - The full directory path of where the FITS image file is to be
;                  written out.
;   file - STRING - The file name of the FITS image file to be written out.
;   maxtry - INTEGER/LONG - Maximum number of attempts at writing the image data
;                           before giving up and returning the "status" value of 
;                           "0" (Default value = 1).
;   data - BYTE/INTEGER/LONG/FLOAT/DOUBLE ARRAY (ANY DIMENSIONS) - The image data that is to be 
;                                                                  written to the FITS image file.
;   header - STRING ARRAY - The header to be written out to the FITS image file.
;                           The module removes the keywords BZERO and BSCALE, since the
;                           image is written out without any offset or scaling applied.
;                           Set this to 'NONE' to write out a standard minimal header.
;                           If this parameter is not a vector with values of STRING 
;                           type, then the module will write out a standard minimal
;                           header.
;
; Output parameters:
;
;   status - INTEGER - If the module successfully wrote out the image data, then "status"
;                      is returned with a value of "1", otherwise it is returned with
;                      a value of "0". 
;
; Author: Dan Bramich (dan.bramich@hotmail.co.uk)
;
; History:
;
;   29/04/2008 - Module created (dmb)

;Check that "dir" and "file" are variables of STRING type

;If "maxtry" is not a positive number of the correct type, then reset its value to "1"

;Check that "data" contains number data

;Check that "header" is a vector with values of STRING type

;If a header is to be written out with the image, then remove the BZERO and BSCALE keywords
;from the header

;Wait until the output directory is available

    ;If no header is to be written out with the image, then write out the image data with a
    ;minimal header

    ;If a header is to be written out with the image, then write out the image data with the
    ;required header information