102 lines
3.8 KiB
HTML
102 lines
3.8 KiB
HTML
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<html lang="en">
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<head>
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<title>Macro define and undefine - STABS</title>
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<meta http-equiv="Content-Type" content="text/html">
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<meta name="description" content="STABS">
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<meta name="generator" content="makeinfo 4.13">
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<link title="Top" rel="start" href="index.html#Top">
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<link rel="prev" href="Types.html#Types" title="Types">
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<link rel="next" href="Symbol-Tables.html#Symbol-Tables" title="Symbol Tables">
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<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
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<!--
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Copyright (C) 1992-2019 Free Software Foundation, Inc.
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Contributed by Cygnus Support. Written by Julia Menapace, Jim Kingdon,
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and David MacKenzie.
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Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU Free Documentation License, Version 1.3 or
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any later version published by the Free Software Foundation; with no
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Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
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Texts. A copy of the license is included in the section entitled ``GNU
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Free Documentation License''.-->
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</head>
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<body>
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<div class="node">
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<a name="Macro-define-and-undefine"></a>
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<p>
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Next: <a rel="next" accesskey="n" href="Symbol-Tables.html#Symbol-Tables">Symbol Tables</a>,
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Previous: <a rel="previous" accesskey="p" href="Types.html#Types">Types</a>,
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Up: <a rel="up" accesskey="u" href="index.html#Top">Top</a>
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<hr>
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</div>
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<h2 class="chapter">6 Representation of #define and #undef</h2>
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<p>This section describes the stabs support for macro define and undefine
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information, supported on some systems. (e.g., with <samp><span class="option">-g3</span></samp>
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<samp><span class="option">-gstabs</span></samp> when using GCC).
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<p>A <code>#define </code><var>macro-name</var> <var>macro-body</var> is represented with
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an <code>N_MAC_DEFINE</code> stab with a string field of
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<var>macro-name</var> <var>macro-body</var>.
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<a name="index-N_005fMAC_005fDEFINE-51"></a>
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An <code>#undef </code><var>macro-name</var> is represented with an
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<code>N_MAC_UNDEF</code> stabs with a string field of simply
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<var>macro-name</var>.
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<a name="index-N_005fMAC_005fUNDEF-52"></a>
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For both <code>N_MAC_DEFINE</code> and <code>N_MAC_UNDEF</code>, the desc field is
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the line number within the file where the corresponding <code>#define</code>
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or <code>#undef</code> occurred.
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<p>For example, the following C code:
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<pre class="example"> #define NONE 42
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#define TWO(a, b) (a + (a) + 2 * b)
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#define ONE(c) (c + 19)
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main(int argc, char *argv[])
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{
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func(NONE, TWO(10, 11));
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func(NONE, ONE(23));
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#undef ONE
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#define ONE(c) (c + 23)
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func(NONE, ONE(-23));
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return (0);
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}
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int global;
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func(int arg1, int arg2)
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{
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global = arg1 + arg2;
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}
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</pre>
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<p class="noindent">produces the following stabs (as well as many others):
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<pre class="example"> .stabs "NONE 42",54,0,1,0
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.stabs "TWO(a,b) (a + (a) + 2 * b)",54,0,2,0
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.stabs "ONE(c) (c + 19)",54,0,3,0
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.stabs "ONE",58,0,10,0
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.stabs "ONE(c) (c + 23)",54,0,11,0
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</pre>
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<p class="noindent">NOTE: In the above example, <code>54</code> is <code>N_MAC_DEFINE</code> and
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<code>58</code> is <code>N_MAC_UNDEF</code>.
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</body></html>
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