;+
; H+
;	TITLE	: get_session_id
;
; 	Author	: Pamme Crandall
; 	Date	: 07/18/06
;
;	$Date: 2006/07/19 00:40:17 $
;	$Source: /lasp/software/src/mm_tdp/src/get_session_id.pro,v $
;  @(#)	$Revision: 1.1 $
;	$Name: version_2-2 $
;	$Locker:  $
;
;
; Purpose:
;   Returns the process id of the session leader to which this 
;   idl session belongs
; Author:
;   Chris Pankratz
; Date:
;   2 August 2002
;
;
;	CATEGORY:
;	<Category of routine here>
;
;	CALLING SEQUENCE:
;	<How routine is called with parameters, optional ones in brackets>
;
;	INPUT PARAMETERS:
;	<List input parameters>
;
;	OPTIONAL KEYWORD PARAMETERS:
;
;       RETURN VALUE:
;       session_id - uniques string that belongs to current idl session
;
;	COMMON BLOCKS:
;	<Describe any common blocks used>
;
;	PROCEDURE:
;	<describe procedure for processing>
;
;-
;	MODIFICATIONS/REVISION LEVEL:
;	MM/DD/YY WHO	WHAT (most recent change first)
;
; H-
;------------------------------------------------------------------------------

function get_session_id

common session_id, session_id

if (n_elements(session_id) eq 0) then begin
  ;print, 'Getting session_id'
  ;spawn, 'ps -fj'
  ;spawn, 'echo "IDL Spawn process = $$"'
  ;spawn, 'echo $$', PID
  ;PID = PID[0]
  ;print, 'IDL Spawn Process = ' + PID
  spawn, "ps -o pid,sid | awk '$1 ~ /'$$'/ {print $2}'", session_id
  session_id = long(session_id[0])
  print, 'IDL Session Process = ' + strtrim(session_id,2)
endif

return, session_id
end