lang/C/the.ansi.c.programming.language/notes.accompany.ansi.c/sx4a.html

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   9 <title>section 1.1: Getting Started</title>
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  15 <H2>section 1.1: Getting Started</H2>
  16
  17 <p>page 6
  18 </p><p>Deep sentence:
  19 <blockquote>With these mechanical details mastered,
  20 everything else is comparatively easy.
  21 </blockquote>The claim that a program as simple as ``hello, world''
  22 is a big hurdle
  23 may seem outrageous,
  24 but it's really quite true.
  25 It <em>is</em> a hurdle:
  26 on an unfamiliar computer,
  27 it can be arbitrarily difficult to figure out how to enter a
  28 text file containing program source,
  29 or how to compile and link it,
  30 or how to invoke it,
  31 or what happened after (if?) it ran.
  32 The most experienced C programmers immediately go back to this
  33 one, simple program whenever they're trying out a new system
  34 or a new way of entering or building programs
  35 or a new way of printing output from within programs.
  36 As they say,
  37 everything else <em>is</em> comparatively easy.
  38 </p><p>One hurdle which the authors don't mention but which many of
  39 you may find yourself facing is the choice of an appropriate
  40 compiler.
  41 On many Unix machines, the <TT>cc</TT> command which the authors
  42 describe is an older compiler which does not recognize modern,
  43 ANSI Standard C syntax.
  44 An old compiler will accept the simple program on page 6,
  45 but it will not accept many of the other programs in the book.
  46 If you find yourself getting baffling compilation errors on
  47 programs which you've typed in exactly as they're shown in the
  48 book, it probably indicates that you're using an older compiler.
  49 On many machines, another compiler called
  50 <TT>acc</TT> or
  51 <TT>gcc</TT> is available,
  52 and you'll want to use it, instead.
  53 </p><p>Deep sentence:
  54 <blockquote><TT>main</TT> will usually call other functions to help perform its job,
  55 some that you wrote,
  56 and others from libraries that are provided for you.
  57 </blockquote>We heard about this already in the Introduction,
  58 but here it is again:
  59 as far as the compiler and the language definition are concerned,
  60 there's no difference between a function that you write
  61 and a function someone else wrote for you,
  62 including a function like <TT>printf</TT>
  63 which seems to be part of the language.
  64 There's nothing magic about <TT>printf</TT>;
  65 there's nothing that it can do that one of your functions couldn't.
  66 (Well,
  67 actually,
  68 there are a few magic,
  69 or at least surprising,
  70 things about <TT>printf</TT>,
  71 but they're magic in ways that your functions can be, too.)
  72 </p><p>There is one slight problem with the simple ``hello, world''
  73 program
  74 in the book.
  75 The problem
  76 will usually be ignored
  77 (that is, the program will usually work correctly),
  78 but if you receive any warning or error messages
  79 or have any problems having to do with
  80 the ``value returned from <TT>main</TT>,''
  81 jump forward to page 26
  82 to learn why <TT>main</TT> ought to end with the line
  83 <pre>   return 0;
  84 </pre></p><hr>
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  93 This page by <a href="http://www.eskimo.com/~scs/">Steve Summit</a>
  94 // <a href="copyright.html">Copyright</a> 1995, 1996
  95 // <a href="mailto:scs@eskimo.com">mail feedback</a>
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