mingw/info/gdb/Tracepoint-Variables.html

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  12 Node:<a name="Tracepoint%20Variables">Tracepoint Variables</a>,
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  17
  18 <h3 class="section">Convenience Variables for Tracepoints</h3>
  19
  20      <dl>
  21 <dt><code>(int) $trace_frame</code>
  22      <dd>The current trace snapshot (a.k.a. <dfn>frame</dfn>) number, or -1 if no
  23 snapshot is selected.
  24
  25      <br><dt><code>(int) $tracepoint</code>
  26      <dd>The tracepoint for the current trace snapshot.
  27
  28      <br><dt><code>(int) $trace_line</code>
  29      <dd>The line number for the current trace snapshot.
  30
  31      <br><dt><code>(char []) $trace_file</code>
  32      <dd>The source file for the current trace snapshot.
  33
  34      <br><dt><code>(char []) $trace_func</code>
  35      <dd>The name of the function containing <code>$tracepoint</code>.
  36 </dl>
  37
  38    <p>Note: <code>$trace_file</code> is not suitable for use in <code>printf</code>,
  39 use <code>output</code> instead.
  40
  41    <p>Here's a simple example of using these convenience variables for
  42 stepping through all the trace snapshots and printing some of their
  43 data.
  44
  45 <pre class="smallexample">     (gdb) <b>tfind start</b>
  46
  47      (gdb) <b>while $trace_frame != -1</b>
  48      &gt; output $trace_file
  49      &gt; printf ", line %d (tracepoint #%d)\n", $trace_line, $tracepoint
  50      &gt; tfind
  51      &gt; end
  52      </pre>
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