gdb: Trace Files
13.4 Using Trace Files
======================
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 'target tfile' command.
'tsave [ -r ] FILENAME'
'tsave [-ctf] DIRNAME'
Save the trace data to FILENAME. By default, this command assumes
that FILENAME refers to the host filesystem, so if necessary GDB
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
'-r' ("remote") to direct the target to save the data directly into
FILENAME in its own filesystem, which may be more efficient if the
trace buffer is very large. (Note, however, that 'target tfile'
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 '-ctf' to save data in CTF format. The "Common
Trace Format" (CTF) is proposed as a trace format that can be
shared by multiple debugging and tracing tools. Please go to
'http://www.efficios.com/ctf' to get more information.
'target tfile FILENAME'
'target ctf DIRNAME'
Use the file named FILENAME or directory named DIRNAME 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. 'tstatus' 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 FILENAME and DIRNAME must be on a
filesystem accessible to the host.
(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
Info Catalog
gdb: Tracepoint Variables
gdb: Tracepoints