lang/C/the.ansi.c.programming.language/notes.accompany.ansi.c/sx5a.html

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   9 <title>section 2.1: Variable Names</title>
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  15 <H2>section 2.1: Variable Names</H2>
  16
  17 <p>Deep sentence:
  18 <blockquote>Don't begin variable names with underscore, however,
  19 since library routines often use such names.
  20 </blockquote>If you happen to pick a name which ``collides'' with
  21 (is the same as)
  22 a name already chosen by a library routine,
  23 either your code
  24 or the library routine
  25 (or both)
  26 won't work.
  27 Naming issues become very significant in large projects,
  28 and problems can be avoided by setting guidelines for who may
  29 use which names.
  30 One of these guidelines is simply that user code should not use
  31 names beginning with an underscore,
  32 because these names are
  33 (for the most part)
  34 ``reserved to the implementation''
  35 (that is,
  36 reserved for use by the compiler and the standard library).
  37 </p><p>Note that case is significant;
  38 assuming that case is ignored
  39 (as it is with some other programming languages and operating systems)
  40 can lead to real frustration.
  41 </p><p>The convention that all-upper-case names are used for
  42 symbolic constants
  43 (i.e. as
  44 created with the <TT>#define</TT> directive,
  45 which we learned about in section 1.4)
  46 is arbitrary, but useful.
  47 Like the various conventions for code layout (page 10),
  48 this convention is a good one to accept
  49 (i.e. not get too creative about),
  50 until you have some very good reason for altering it.
  51 </p><p>Deep sentence:
  52 <blockquote>Keywords like
  53 <TT>if</TT>, <TT>else</TT>, <TT>int</TT>, <TT>float</TT>, etc.,
  54 are reserved;
  55 you can't use them as variable names.
  56 </blockquote>You can find the complete list of keywords
  57 in appendix A2.4 on page 192.
  58 </p><hr>
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  67 This page by <a href="http://www.eskimo.com/~scs/">Steve Summit</a>
  68 // <a href="copyright.html">Copyright</a> 1995, 1996
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