function existdir, test_dir, rtcode=rtcode

;+ 
; function existdir, test_dir, rtcode=rtcode
; function: checks existence of DIRECTORY
; --------------------------------------------------------------------------
; START OF DESCRIPTION
; 
; function          IPI, U Hannover 06'94
;                                   06'94: 
;
; METHOD:           checks existence of DIRECTORY
;                   uses: OPENR,...,ERROR=ERROR
;
; INPUT  PARAMETER: test_dir    directory to test
; 
; RETURNS:          1:          exists
;                   0:          does NOT exists
;
; INPUT KEYWORDS  : none
; 
; OUTPUT KEYWORDS : rtcode      Return-code : 0 for o.k., -1 for ERROR
; 
; EXAMPLE:
; 
; print, existdir('$HOME')
; 
; END   OF DESCRIPTION
; --------------------------------------------------------------------------
;-

ret_val = 0					; return - value
rtcode 	= 0					; Return - code


; --------------------------------------------------------------------------
; test input

if n_params() ne 1 then begin
  print,"The number of parameters was wrong:",n_params() 
  doc_library,"existdir"
  return, ret_val
endif

if  n_elements(test_dir)  eq 0  then begin
	message, 'TEST_+DIR UNDEFINED : ', /info
	return, ret_val
endif


; --------------------------------------------------------------------------
; OS ?

case !version.os of
     'windows':	dir_delim = '\'
     else:	dir_delim = '/'
endcase


; --------------------------------------------------------------------------
; re-store

test	= test_dir


; --------------------------------------------------------------------------
; length

len	= strlen(test)


; --------------------------------------------------------------------------
; delimiter at end?

if  strmid(test, len-1, 1) eq  dir_delim  $
    then	test = strmid(test, 0, len-1)


; --------------------------------------------------------------------------
; open

openr, uni, test, /get_lun, error=error


; --------------------------------------------------------------------------
; check

if  error ne 0  then  return, 0


; --------------------------------------------------------------------------
; close

free_lun, uni


; --------------------------------------------------------------------------
; return & end

rtcode = 0

return, 1
end