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| <h3 class="section">13.4 Using Trace Files</h3> |
| |
| <p><a name="index-trace-files-943"></a> |
| In some situations, the target running a trace experiment may no |
| longer be available; perhaps it crashed, or the hardware was needed |
| for a different activity. To handle these cases, you can arrange to |
| dump the trace data into a file, and later use that file as a source |
| of trace data, via the <code>target tfile</code> command. |
| |
| |
| <a name="index-tsave-944"></a> |
| <dl><dt><code>tsave [ -r ] </code><var>filename</var><dt><code>tsave [-ctf] </code><var>dirname</var><dd>Save the trace data to <var>filename</var>. By default, this command |
| assumes that <var>filename</var> refers to the host filesystem, so if |
| necessary <span class="sc">gdb</span> will copy raw trace data up from the target and |
| then save it. If the target supports it, you can also supply the |
| optional argument <code>-r</code> (“remote”) to direct the target to save |
| the data directly into <var>filename</var> in its own filesystem, which may be |
| more efficient if the trace buffer is very large. (Note, however, that |
| <code>target tfile</code> can only read from files accessible to the host.) |
| By default, this command will save trace frame in tfile format. |
| You can supply the optional argument <code>-ctf</code> to save data in CTF |
| format. The <dfn>Common Trace Format</dfn> (CTF) is proposed as a trace format |
| that can be shared by multiple debugging and tracing tools. Please go to |
| <<code>http://www.efficios.com/ctf</code>> to get more information. |
| |
| <p><a name="index-target-tfile-945"></a><a name="index-tfile-946"></a><a name="index-target-ctf-947"></a><a name="index-ctf-948"></a><br><dt><code>target tfile </code><var>filename</var><dt><code>target ctf </code><var>dirname</var><dd>Use the file named <var>filename</var> or directory named <var>dirname</var> as |
| a source of trace data. Commands that examine data work as they do with |
| a live target, but it is not possible to run any new trace experiments. |
| <code>tstatus</code> will report the state of the trace run at the moment |
| the data was saved, as well as the current trace frame you are examining. |
| Both <var>filename</var> and <var>dirname</var> must be on a filesystem accessible to |
| the host. |
| |
| <pre class="smallexample"> (gdb) target ctf ctf.ctf |
| (gdb) tfind |
| Found trace frame 0, tracepoint 2 |
| 39 ++a; /* set tracepoint 1 here */ |
| (gdb) tdump |
| Data collected at tracepoint 2, trace frame 0: |
| i = 0 |
| a = 0 |
| b = 1 '\001' |
| c = {"123", "456", "789", "123", "456", "789"} |
| d = {{{a = 1, b = 2}, {a = 3, b = 4}}, {{a = 5, b = 6}, {a = 7, b = 8}}} |
| (gdb) p b |
| $1 = 1 |
| </pre> |
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