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<a name="Global-Variables"></a>
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Next: <a href="Register-Variables.html#Register-Variables" accesskey="n" rel="next">Register Variables</a>, Previous: <a href="Stack-Variables.html#Stack-Variables" accesskey="p" rel="prev">Stack Variables</a>, Up: <a href="Variables.html#Variables" accesskey="u" rel="up">Variables</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Symbol-Types-Index.html#Symbol-Types-Index" title="Index" rel="index">Index</a>]</p>
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<a name="Global-Variables-1"></a>
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<h3 class="section">4.2 Global Variables</h3>
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<a name="index-N_005fGSYM"></a>
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<a name="index-C_005fGSYM"></a>
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<p>A variable whose scope is not specific to just one source file is
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represented by the ‘<samp>G</samp>’ symbol descriptor. These stabs use the
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<code>N_GSYM</code> stab type (C_GSYM for XCOFF). The type information for
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the stab (see <a href="String-Field.html#String-Field">String Field</a>) gives the type of the variable.
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</p>
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<p>For example, the following source code:
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</p>
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<div class="example">
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<pre class="example">char g_foo = 'c';
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</pre></div>
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<p>yields the following assembly code:
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</p>
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<div class="example">
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<pre class="example">.stabs "g_foo:G2",32,0,0,0 # <span class="roman">32 is N_GSYM</span>
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.global _g_foo
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.data
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_g_foo:
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.byte 99
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</pre></div>
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<p>The address of the variable represented by the <code>N_GSYM</code> is not
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contained in the <code>N_GSYM</code> stab. The debugger gets this information
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from the external symbol for the global variable. In the example above,
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the <code>.global _g_foo</code> and <code>_g_foo:</code> lines tell the assembler to
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produce an external symbol.
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</p>
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<p>Some compilers, like GCC, output <code>N_GSYM</code> stabs only once, where
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the variable is defined. Other compilers, like SunOS4 /bin/cc, output a
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<code>N_GSYM</code> stab for each compilation unit which references the
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variable.
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