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<h3 class="section">7.86 <code>.stabd, .stabn, .stabs</code></h3>
<p><a name="index-symbolic-debuggers_002c-information-for-470"></a><a name="index-g_t_0040code_007bstab_0040var_007bx_007d_007d-directives-471"></a>There are three directives that begin ‘<samp><span class="samp">.stab</span></samp>’.
All emit symbols (see <a href="Symbols.html#Symbols">Symbols</a>), for use by symbolic debuggers.
The symbols are not entered in the <samp><span class="command">as</span></samp> hash table: they
cannot be referenced elsewhere in the source file.
Up to five fields are required:
<dl>
<dt><var>string</var><dd>This is the symbol's name. It may contain any character except
‘<samp><span class="samp">\000</span></samp>’, so is more general than ordinary symbol names. Some
debuggers used to code arbitrarily complex structures into symbol names
using this field.
<br><dt><var>type</var><dd>An absolute expression. The symbol's type is set to the low 8 bits of
this expression. Any bit pattern is permitted, but <code>ld</code>
and debuggers choke on silly bit patterns.
<br><dt><var>other</var><dd>An absolute expression. The symbol's “other” attribute is set to the
low 8 bits of this expression.
<br><dt><var>desc</var><dd>An absolute expression. The symbol's descriptor is set to the low 16
bits of this expression.
<br><dt><var>value</var><dd>An absolute expression which becomes the symbol's value.
</dl>
<p>If a warning is detected while reading a <code>.stabd</code>, <code>.stabn</code>,
or <code>.stabs</code> statement, the symbol has probably already been created;
you get a half-formed symbol in your object file. This is
compatible with earlier assemblers!
<a name="index-g_t_0040code_007bstabd_007d-directive-472"></a>
<dl><dt><code>.stabd </code><var>type</var><code> , </code><var>other</var><code> , </code><var>desc</var><dd>
The “name” of the symbol generated is not even an empty string.
It is a null pointer, for compatibility. Older assemblers used a
null pointer so they didn't waste space in object files with empty
strings.
<p>The symbol's value is set to the location counter,
relocatably. When your program is linked, the value of this symbol
is the address of the location counter when the <code>.stabd</code> was
assembled.
<p><a name="index-g_t_0040code_007bstabn_007d-directive-473"></a><br><dt><code>.stabn </code><var>type</var><code> , </code><var>other</var><code> , </code><var>desc</var><code> , </code><var>value</var><dd>The name of the symbol is set to the empty string <code>""</code>.
<p><a name="index-g_t_0040code_007bstabs_007d-directive-474"></a><br><dt><code>.stabs </code><var>string</var><code> , </code><var>type</var><code> , </code><var>other</var><code> , </code><var>desc</var><code> , </code><var>value</var><dd>All five fields are specified.
</dl>
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