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Text File  |  1992-12-31  |  1.0 KB  |  36 lines
  1. Newsgroups: comp.lang.idl-pvwave
  2. Path: sparky!uunet!wupost!micro-heart-of-gold.mit.edu!xn.ll.mit.edu!ll.mit.edu!knight
  3. From: knight@ll.mit.edu (Fred Knight)
  4. Subject: tape I/O under Unix: eof always true?
  5. Message-ID: <1992Dec31.141848.354@ll.mit.edu>
  6. Originator: knight@ll.mit.edu (Fred Knight)
  7. Sender: news@ll.mit.edu
  8. Reply-To: knight@ll.mit.edu (Fred Knight)
  9. Organization: Group 45, MIT Lincoln Lab.
  10. Date: Thu, 31 Dec 92 14:18:48 GMT
  11. Lines: 23
  12.  
  13.  
  14.  
  15. Can anybody give me some help on IDL's handling of eof while reading
  16. tape under Unix?  The following test fails.  I mount a (test) tar tape
  17. and do the following:
  18.  
  19. IDL> openr,lun,/get_lun,'/dev/rst0'
  20. IDL> print,eof(lun)
  21.        1                ; <==== Why? Shouldn't it be zero?
  22. IDL> point_lun,lun,100
  23. IDL> print,eof(lun)   
  24.        1                ; <==== Same question.
  25. IDL> a=bytarr(2048)
  26. IDL> readu,lun,a
  27. IDL> print,eof(lun)
  28.        1                ; <==== Same question.
  29.  
  30. Thanks for any help,
  31.  
  32. Fred
  33. -- 
  34. =Fred Knight (knight@ll.mit.edu)    (617) 981-2027
  35.  C-483\\MIT Lincoln Laboratory\\244 Wood Street\\Lexington, MA  02173
  36.