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Text File  |  1992-08-27  |  1.2 KB  |  33 lines
  1. Path: sparky!uunet!cs.utexas.edu!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!usenet.coe.montana.edu!news.u.washington.edu!milton!chuckb
  2. From: chuckb@milton.u.washington.edu (Chuck Bass)
  3. Newsgroups: comp.lang.c
  4. Subject: Re: Most difficult part of learning C?
  5. Message-ID: <chuckb.714980690@milton>
  6. Date: 28 Aug 92 05:44:50 GMT
  7. References: <1992Aug25.180919.10370@samba.oit.unc.edu> <behrenss.714775792@hphalle6> <chuckb.714781695@milton> <17g9mlINNsu1@early-bird.think.com> <1992Aug27.005328.3075@kong.gsfc.nasa.gov> <15232@ksr.com>
  8. Sender: news@u.washington.edu (USENET News System)
  9. Organization: University of Washington
  10. Lines: 21
  11.  
  12. One source of confusion that I had was the preprocessor.  Not
  13. with macros or defines but having multiple declarations of
  14. variables, typedefs, structures when files were included more
  15. than once for some reason.  This of course leads to
  16. understanding whe the following is at the top of many headers:
  17.  
  18. #ifndef _THIS_HEADER_DEFINED
  19. #define _THIS_HEADER_DEFINED
  20. ;
  21. ;your header stuff goes here
  22. ;
  23. ;
  24. #endif
  25.  
  26. I pulled a few hairs catching this little problem.
  27.  
  28.  
  29. Chuck Bass
  30. College of Forest-Systems Engineering
  31. University of Washington
  32. chuckb@u.washington.edu
  33.