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  1. Path: sparky!uunet!spool.mu.edu!sgiblab!nec-gw!nec-tyo!wnoc-tyo-news!scslwide!wsgw!wsservra!onoe
  2. From: dave@mizar.csis.dit.csiro.au (David Campbell)
  3. Newsgroups: fj.mail-lists.x-window
  4. Subject: What are the null macros for X types?
  5. Message-ID: <1992Dec30.091244.1885@sm.sony.co.jp>
  6. Date: 30 Dec 92 09:12:44 GMT
  7. Sender: onoe@sm.sony.co.jp (Atsushi Onoe)
  8. Distribution: fj
  9. Organization: CSIRO Division of Information Technology
  10. Lines: 27
  11. Approved: michael@sm.sony.co.jp
  12.  
  13. Date: Wed, 30 Dec 1992 07:11:40 GMT
  14. Message-Id: <1992Dec30.071140.12876@csis.dit.csiro.au>
  15. Newsgroups: comp.windows.x
  16. Sender: xpert-request@expo.lcs.mit.edu
  17.  
  18. X defines many types (eg Display, Window, Pixmap, Colormap).   Some of these
  19. types are used as pointers (eg Display), but others are actually unsigned
  20. longs (eg Window, Pixmap, Colormap).
  21.  
  22. Is XCreateWindow guaranteed to never return 0?  I can't seem to find any detail
  23. of such semantics; otherwise I would assume that an acceptable null value for
  24. a window is 0.  Is there a macro which can be used instead of hardcoding 0? There seem to be a handful of macros like NULL, None, etc but I don't know
  25. which to use and NULL seems inappropriate because a Window is not a pointer.
  26.  
  27. Thanks,
  28. -- 
  29.   +--------------------------------------------------+-----------------------+
  30.   | Dave Campbell                                    |            UNIX & C++ |
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  36.   | AUSTRALIA               | dave@csis.dit.csiro.au |                       |
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  40.