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   9 <title>Chapter 25: Variable-Length Argument Lists</title>
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  15 <H1>Chapter 25: Variable-Length Argument Lists</H1>
  16
  17 <p>
  18 All of the functions we've written so far
  19 have taken a fixed number of arguments,
  20 and we've been careful to call the functions
  21 always passing them the correct number of arguments,
  22 and we've been tending to use
  23 explicit function prototype declarations
  24 so that the compiler can verify
  25 that we call functions with the correct number of arguments.
  26 But what about <TT>printf</TT>?
  27 Sometimes we call it with one argument,
  28 but often we pass it additional arguments.
  29 Why doesn't the compiler complain?
  30 How can <TT>printf</TT> access the extra arguments we pass to it,
  31 when it can't know how many of them there will be
  32 or what types they will have,
  33 such that it can't possibly declare
  34 conventional function parameters for them?
  35 </p><p>In this chapter we'll discuss the <dfn>variable-length argument lists</dfn>
  36 (often discussed under the shorthand term ``varargs'')
  37 which allow functions such as <TT>printf</TT> to be written.
  38 </p><p><a href="sx11a.html" rel=subdocument>25.1 Declaring ``varargs'' Functions</a></p>
  39 <p><a href="sx11b.html" rel=subdocument>25.2 Writing a ``varargs'' Function</a></p>
  40 <p><a href="sx11c.html" rel=subdocument>25.3 Special Issues with Varargs Functions</a></p>
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