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Previous: <a href="Argument-Prescan.html#Argument-Prescan" accesskey="p" rel="prev">Argument Prescan</a>, Up: <a href="Macro-Pitfalls.html#Macro-Pitfalls" accesskey="u" rel="up">Macro Pitfalls</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index-of-Directives.html#Index-of-Directives" title="Index" rel="index">Index</a>]</p>
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<a name="Newlines-in-Arguments-1"></a>
<h4 class="subsection">3.10.7 Newlines in Arguments</h4>
<a name="index-newlines-in-macro-arguments"></a>
<p>The invocation of a function-like macro can extend over many logical
lines. However, in the present implementation, the entire expansion
comes out on one line. Thus line numbers emitted by the compiler or
debugger refer to the line the invocation started on, which might be
different to the line containing the argument causing the problem.
</p>
<p>Here is an example illustrating this:
</p>
<div class="smallexample">
<pre class="smallexample">#define ignore_second_arg(a,b,c) a; c
ignore_second_arg (foo (),
ignored (),
syntax error);
</pre></div>
<p>The syntax error triggered by the tokens <code>syntax error</code> results in
an error message citing line three—the line of ignore_second_arg—
even though the problematic code comes from line five.
</p>
<p>We consider this a bug, and intend to fix it in the near future.
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