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<title>Debugging with GDB: Symbol Errors</title>
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<a name="Symbol-Errors"></a>
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<hr>
<a name="Errors-Reading-Symbol-Files"></a>
<h3 class="section">18.5 Errors Reading Symbol Files</h3>
<p>While reading a symbol file, <small>GDB</small> occasionally encounters problems,
such as symbol types it does not recognize, or known bugs in compiler
output. By default, <small>GDB</small> does not notify you of such problems, since
they are relatively common and primarily of interest to people
debugging compilers. If you are interested in seeing information
about ill-constructed symbol tables, you can either ask <small>GDB</small> to print
only one message about each such type of problem, no matter how many
times the problem occurs; or you can ask <small>GDB</small> to print more messages,
to see how many times the problems occur, with the <code>set
complaints</code> command (see <a href="Messages_002fWarnings.html#Messages_002fWarnings">Optional Warnings and
Messages</a>).
</p>
<p>The messages currently printed, and their meanings, include:
</p>
<dl compact="compact">
<dt><code>inner block not inside outer block in <var>symbol</var></code></dt>
<dd>
<p>The symbol information shows where symbol scopes begin and end
(such as at the start of a function or a block of statements). This
error indicates that an inner scope block is not fully contained
in its outer scope blocks.
</p>
<p><small>GDB</small> circumvents the problem by treating the inner block as if it had
the same scope as the outer block. In the error message, <var>symbol</var>
may be shown as &ldquo;<code>(don't know)</code>&rdquo; if the outer block is not a
function.
</p>
</dd>
<dt><code>block at <var>address</var> out of order</code></dt>
<dd>
<p>The symbol information for symbol scope blocks should occur in
order of increasing addresses. This error indicates that it does not
do so.
</p>
<p><small>GDB</small> does not circumvent this problem, and has trouble
locating symbols in the source file whose symbols it is reading. (You
can often determine what source file is affected by specifying
<code>set verbose on</code>. See <a href="Messages_002fWarnings.html#Messages_002fWarnings">Optional Warnings and
Messages</a>.)
</p>
</dd>
<dt><code>bad block start address patched</code></dt>
<dd>
<p>The symbol information for a symbol scope block has a start address
smaller than the address of the preceding source line. This is known
to occur in the SunOS 4.1.1 (and earlier) C compiler.
</p>
<p><small>GDB</small> circumvents the problem by treating the symbol scope block as
starting on the previous source line.
</p>
</dd>
<dt><code>bad string table offset in symbol <var>n</var></code></dt>
<dd>
<a name="index-foo"></a>
<p>Symbol number <var>n</var> contains a pointer into the string table which is
larger than the size of the string table.
</p>
<p><small>GDB</small> circumvents the problem by considering the symbol to have the
name <code>foo</code>, which may cause other problems if many symbols end up
with this name.
</p>
</dd>
<dt><code>unknown symbol type <code>0x<var>nn</var></code></code></dt>
<dd>
<p>The symbol information contains new data types that <small>GDB</small> does
not yet know how to read. <code>0x<var>nn</var></code> is the symbol type of the
uncomprehended information, in hexadecimal.
</p>
<p><small>GDB</small> circumvents the error by ignoring this symbol information.
This usually allows you to debug your program, though certain symbols
are not accessible. If you encounter such a problem and feel like
debugging it, you can debug <code>gdb</code> with itself, breakpoint
on <code>complain</code>, then go up to the function <code>read_dbx_symtab</code>
and examine <code>*bufp</code> to see the symbol.
</p>
</dd>
<dt><code>stub type has NULL name</code></dt>
<dd>
<p><small>GDB</small> could not find the full definition for a struct or class.
</p>
</dd>
<dt><code>const/volatile indicator missing (ok if using g++ v1.x), got&hellip;</code></dt>
<dd><p>The symbol information for a C<tt>++</tt> member function is missing some
information that recent versions of the compiler should have output for
it.
</p>
</dd>
<dt><code>info mismatch between compiler and debugger</code></dt>
<dd>
<p><small>GDB</small> could not parse a type specification output by the compiler.
</p>
</dd>
</dl>
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