FUNCTION dustem_read_lambda,file,silent=silent,help=help

;+
; NAME:
;   dustem_read_lambda
;
; PURPOSE:
;   reads information relating to wavelengths used for the dust spectra
;
; CATEGORY:
;    DustEMWrap, Distributed, LowLevel, Initialization
;
; CALLING SEQUENCE:
;   st=dustem_read_lambda(file)
;
; INPUTS:
;    file  : input file to be read
;
; OPTIONAL INPUT PARAMETERS:
;
; OUTPUTS:
;    st   : dustem data structure
;
; OPTIONAL OUTPUT PARAMETERS:
;
; ACCEPTED KEY-WORDS:
;    help     : writes this help
;
; COMMON BLOCKS:
;    None
;
; SIDE EFFECTS:
;
; RESTRICTIONS:
;    The DustEM fortran code must be installed
;    The DustEMWrap IDL code must be installed
;
; PROCEDURES AND SUBROUTINES USED:  
;
; EXAMPLES:
;
; MODIFICATION HISTORY:
;    Evolution details on the DustEMWrap gitlab.
;    See http://dustemwrap.irap.omp.eu/ for FAQ and help.  
;-
  
IF keyword_set(help) THEN BEGIN
   doc_library,'dustem_read_lambda'
   st=0.
   goto,the_end
ENDIF

readcol,file,lambda,silent=silent,comment='#',format='F'

;this will actually read the number of wavelengths as the first value in the output structure 

;ie st.(0)
;{
;    "LAMBDA": 800.00000
;}

;The wrapper formerly dropped this leading element in dustem_get_wavelengths() but 
;we now enforce this fix here

Nlambda=n_elements(lambda)-1 ; i.e. remove first element

one_st={lambda:0.}
st=replicate(one_st,Nlambda)

st.lambda=lambda[1:Nlambda] 

the_end:

return,st

END