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<h2 class="appendix">Appendix C Maintenance Commands</h2>

<p><a name="index-maintenance-commands-2300"></a><a name="index-internal-commands-2301"></a>
In addition to commands intended for <span class="sc">gdb</span> users, <span class="sc">gdb</span>
includes a number of commands intended for <span class="sc">gdb</span> developers,
that are not documented elsewhere in this manual.  These commands are
provided here for reference.  (For commands that turn on debugging
messages, see <a href="Debugging-Output.html#Debugging-Output">Debugging Output</a>.)

     
<a name="index-maint-agent-2302"></a>
<a name="index-maint-agent_002deval-2303"></a>
<dl><dt><code>maint agent </code><var>expression</var><dt><code>maint agent-eval </code><var>expression</var><dd>Translate the given <var>expression</var> into remote agent bytecodes. 
This command is useful for debugging the Agent Expression mechanism
(see <a href="Agent-Expressions.html#Agent-Expressions">Agent Expressions</a>).  The &lsquo;<samp><span class="samp">agent</span></samp>&rsquo; version produces an
expression useful for data collection, such as by tracepoints, while
&lsquo;<samp><span class="samp">maint agent-eval</span></samp>&rsquo; produces an expression that evaluates directly
to a result.  For instance, a collection expression for <code>globa +
globb</code> will include bytecodes to record four bytes of memory at each
of the addresses of <code>globa</code> and <code>globb</code>, while discarding
the result of the addition, while an evaluation expression will do the
addition and return the sum.

     <p><a name="index-maint-info-breakpoints-2304"></a><br><dt><code><a name="maint-info-breakpoints"></a>maint info breakpoints</code><dd>Using the same format as &lsquo;<samp><span class="samp">info breakpoints</span></samp>&rsquo;, display both the
breakpoints you've set explicitly, and those <span class="sc">gdb</span> is using for
internal purposes.  Internal breakpoints are shown with negative
breakpoint numbers.  The type column identifies what kind of breakpoint
is shown:

          <dl>
<dt><code>breakpoint</code><dd>Normal, explicitly set breakpoint.

          <br><dt><code>watchpoint</code><dd>Normal, explicitly set watchpoint.

          <br><dt><code>longjmp</code><dd>Internal breakpoint, used to handle correctly stepping through
<code>longjmp</code> calls.

          <br><dt><code>longjmp resume</code><dd>Internal breakpoint at the target of a <code>longjmp</code>.

          <br><dt><code>until</code><dd>Temporary internal breakpoint used by the <span class="sc">gdb</span> <code>until</code> command.

          <br><dt><code>finish</code><dd>Temporary internal breakpoint used by the <span class="sc">gdb</span> <code>finish</code> command.

          <br><dt><code>shlib events</code><dd>Shared library events.

     </dl>

     <p><a name="index-set-displaced_002dstepping-2305"></a><a name="index-show-displaced_002dstepping-2306"></a><a name="index-displaced-stepping-support-2307"></a><a name="index-out_002dof_002dline-single_002dstepping-2308"></a><br><dt><code>set displaced-stepping</code><dt><code>show displaced-stepping</code><dd>Control whether or not <span class="sc">gdb</span> will do <dfn>displaced stepping</dfn>
if the target supports it.  Displaced stepping is a way to single-step
over breakpoints without removing them from the inferior, by executing
an out-of-line copy of the instruction that was originally at the
breakpoint location.  It is also known as out-of-line single-stepping.

          <dl>
<dt><code>set displaced-stepping on</code><dd>If the target architecture supports it, <span class="sc">gdb</span> will use
displaced stepping to step over breakpoints.

          <br><dt><code>set displaced-stepping off</code><dd><span class="sc">gdb</span> will not use displaced stepping to step over breakpoints,
even if such is supported by the target architecture.

          <p><a name="index-non_002dstop-mode_002c-and-_0040samp_007bset-displaced_002dstepping_007d-2309"></a><br><dt><code>set displaced-stepping auto</code><dd>This is the default mode.  <span class="sc">gdb</span> will use displaced stepping
only if non-stop mode is active (see <a href="Non_002dStop-Mode.html#Non_002dStop-Mode">Non-Stop Mode</a>) and the target
architecture supports displaced stepping. 
</dl>

     <p><a name="index-maint-check_002dsymtabs-2310"></a><br><dt><code>maint check-symtabs</code><dd>Check the consistency of psymtabs and symtabs.

     <p><a name="index-maint-cplus-first_005fcomponent-2311"></a><br><dt><code>maint cplus first_component </code><var>name</var><dd>Print the first C<tt>++</tt> class/namespace component of <var>name</var>.

     <p><a name="index-maint-cplus-namespace-2312"></a><br><dt><code>maint cplus namespace</code><dd>Print the list of possible C<tt>++</tt> namespaces.

     <p><a name="index-maint-demangle-2313"></a><br><dt><code>maint demangle </code><var>name</var><dd>Demangle a C<tt>++</tt> or Objective-C mangled <var>name</var>.

     <p><a name="index-maint-deprecate-2314"></a><a name="index-maint-undeprecate-2315"></a><a name="index-deprecated-commands-2316"></a><br><dt><code>maint deprecate </code><var>command</var> <span class="roman">[</span><var>replacement</var><span class="roman">]</span><dt><code>maint undeprecate </code><var>command</var><dd>Deprecate or undeprecate the named <var>command</var>.  Deprecated commands
cause <span class="sc">gdb</span> to issue a warning when you use them.  The optional
argument <var>replacement</var> says which newer command should be used in
favor of the deprecated one; if it is given, <span class="sc">gdb</span> will mention
the replacement as part of the warning.

     <p><a name="index-maint-dump_002dme-2317"></a><br><dt><code>maint dump-me</code><dd><a name="index-g_t_0040code_007bSIGQUIT_007d-signal_002c-dump-core-of-_0040value_007bGDBN_007d-2318"></a>Cause a fatal signal in the debugger and force it to dump its core. 
This is supported only on systems which support aborting a program
with the <code>SIGQUIT</code> signal.

     <p><a name="index-maint-internal_002derror-2319"></a><a name="index-maint-internal_002dwarning-2320"></a><br><dt><code>maint internal-error </code><span class="roman">[</span><var>message-text</var><span class="roman">]</span><dt><code>maint internal-warning </code><span class="roman">[</span><var>message-text</var><span class="roman">]</span><dd>Cause <span class="sc">gdb</span> to call the internal function <code>internal_error</code>
or <code>internal_warning</code> and hence behave as though an internal error
or internal warning has been detected.  In addition to reporting the
internal problem, these functions give the user the opportunity to
either quit <span class="sc">gdb</span> or create a core file of the current
<span class="sc">gdb</span> session.

     <p>These commands take an optional parameter <var>message-text</var> that is
used as the text of the error or warning message.

     <p>Here's an example of using <code>internal-error</code>:

     <pre class="smallexample">          (gdb) <kbd>maint internal-error testing, 1, 2</kbd>
          .../maint.c:121: internal-error: testing, 1, 2
          A problem internal to GDB has been detected.  Further
          debugging may prove unreliable.
          Quit this debugging session? (y or n) <kbd>n</kbd>
          Create a core file? (y or n) <kbd>n</kbd>
          (gdb)
</pre>
     <p><a name="index-g_t_0040value_007bGDBN_007d-internal-error-2321"></a><a name="index-internal-errors_002c-control-of-_0040value_007bGDBN_007d-behavior-2322"></a>
<a name="index-maint-set-internal_002derror-2323"></a><a name="index-maint-show-internal_002derror-2324"></a><a name="index-maint-set-internal_002dwarning-2325"></a><a name="index-maint-show-internal_002dwarning-2326"></a><br><dt><code>maint set internal-error </code><var>action</var><code> [ask|yes|no]</code><dt><code>maint show internal-error </code><var>action</var><dt><code>maint set internal-warning </code><var>action</var><code> [ask|yes|no]</code><dt><code>maint show internal-warning </code><var>action</var><dd>When <span class="sc">gdb</span> reports an internal problem (error or warning) it
gives the user the opportunity to both quit <span class="sc">gdb</span> and create a
core file of the current <span class="sc">gdb</span> session.  These commands let you
override the default behaviour for each particular <var>action</var>,
described in the table below.

          <dl>
<dt>&lsquo;<samp><span class="samp">quit</span></samp>&rsquo;<dd>You can specify that <span class="sc">gdb</span> should always (yes) or never (no)
quit.  The default is to ask the user what to do.

          <br><dt>&lsquo;<samp><span class="samp">corefile</span></samp>&rsquo;<dd>You can specify that <span class="sc">gdb</span> should always (yes) or never (no)
create a core file.  The default is to ask the user what to do. 
</dl>

     <p><a name="index-maint-packet-2327"></a><br><dt><code>maint packet </code><var>text</var><dd>If <span class="sc">gdb</span> is talking to an inferior via the serial protocol,
then this command sends the string <var>text</var> to the inferior, and
displays the response packet.  <span class="sc">gdb</span> supplies the initial
&lsquo;<samp><span class="samp">$</span></samp>&rsquo; character, the terminating &lsquo;<samp><span class="samp">#</span></samp>&rsquo; character, and the
checksum.

     <p><a name="index-maint-print-architecture-2328"></a><br><dt><code>maint print architecture </code><span class="roman">[</span><var>file</var><span class="roman">]</span><dd>Print the entire architecture configuration.  The optional argument
<var>file</var> names the file where the output goes.

     <p><a name="index-maint-print-c_002dtdesc-2329"></a><br><dt><code>maint print c-tdesc</code><dd>Print the current target description (see <a href="Target-Descriptions.html#Target-Descriptions">Target Descriptions</a>) as
a C source file.  The created source file can be used in <span class="sc">gdb</span>
when an XML parser is not available to parse the description.

     <p><a name="index-maint-print-dummy_002dframes-2330"></a><br><dt><code>maint print dummy-frames</code><dd>Prints the contents of <span class="sc">gdb</span>'s internal dummy-frame stack.

     <pre class="smallexample">          (gdb) <kbd>b add</kbd>
          ...
          (gdb) <kbd>print add(2,3)</kbd>
          Breakpoint 2, add (a=2, b=3) at ...
          58	  return (a + b);
          The program being debugged stopped while in a function called from GDB.
          ...
          (gdb) <kbd>maint print dummy-frames</kbd>
          0x1a57c80: pc=0x01014068 fp=0x0200bddc sp=0x0200bdd6
           top=0x0200bdd4 id={stack=0x200bddc,code=0x101405c}
           call_lo=0x01014000 call_hi=0x01014001
          (gdb)
</pre>
     <p>Takes an optional file parameter.

     <p><a name="index-maint-print-registers-2331"></a><a name="index-maint-print-raw_002dregisters-2332"></a><a name="index-maint-print-cooked_002dregisters-2333"></a><a name="index-maint-print-register_002dgroups-2334"></a><br><dt><code>maint print registers </code><span class="roman">[</span><var>file</var><span class="roman">]</span><dt><code>maint print raw-registers </code><span class="roman">[</span><var>file</var><span class="roman">]</span><dt><code>maint print cooked-registers </code><span class="roman">[</span><var>file</var><span class="roman">]</span><dt><code>maint print register-groups </code><span class="roman">[</span><var>file</var><span class="roman">]</span><dd>Print <span class="sc">gdb</span>'s internal register data structures.

     <p>The command <code>maint print raw-registers</code> includes the contents of
the raw register cache; the command <code>maint print cooked-registers</code>
includes the (cooked) value of all registers, including registers which
aren't available on the target nor visible to user; and the
command <code>maint print register-groups</code> includes the groups that each
register is a member of.  See <a href="../gdbint/Registers.html#Registers">Registers</a>.

     <p>These commands take an optional parameter, a file name to which to
write the information.

     <p><a name="index-maint-print-reggroups-2335"></a><br><dt><code>maint print reggroups </code><span class="roman">[</span><var>file</var><span class="roman">]</span><dd>Print <span class="sc">gdb</span>'s internal register group data structures.  The
optional argument <var>file</var> tells to what file to write the
information.

     <p>The register groups info looks like this:

     <pre class="smallexample">          (gdb) <kbd>maint print reggroups</kbd>
           Group      Type
           general    user
           float      user
           all        user
           vector     user
           system     user
           save       internal
           restore    internal
</pre>
     <p><a name="index-flushregs-2336"></a><br><dt><code>flushregs</code><dd>This command forces <span class="sc">gdb</span> to flush its internal register cache.

     <p><a name="index-maint-print-objfiles-2337"></a><a name="index-info-for-known-object-files-2338"></a><br><dt><code>maint print objfiles</code><dd>Print a dump of all known object files.  For each object file, this
command prints its name, address in memory, and all of its psymtabs
and symtabs.

     <p><a name="index-maint-print-section_002dscripts-2339"></a><a name="index-info-for-known-_002edebug_005fgdb_005fscripts_002dloaded-scripts-2340"></a><br><dt><code>maint print section-scripts [</code><var>regexp</var><code>]</code><dd>Print a dump of scripts specified in the <code>.debug_gdb_section</code> section. 
If <var>regexp</var> is specified, only print scripts loaded by object files
matching <var>regexp</var>. 
For each script, this command prints its name as specified in the objfile,
and the full path if known. 
See <a href="_002edebug_005fgdb_005fscripts-section.html#g_t_002edebug_005fgdb_005fscripts-section">.debug_gdb_scripts section</a>.

     <p><a name="index-maint-print-statistics-2341"></a><a name="index-bcache-statistics-2342"></a><br><dt><code>maint print statistics</code><dd>This command prints, for each object file in the program, various data
about that object file followed by the byte cache (<dfn>bcache</dfn>)
statistics for the object file.  The objfile data includes the number
of minimal, partial, full, and stabs symbols, the number of types
defined by the objfile, the number of as yet unexpanded psym tables,
the number of line tables and string tables, and the amount of memory
used by the various tables.  The bcache statistics include the counts,
sizes, and counts of duplicates of all and unique objects, max,
average, and median entry size, total memory used and its overhead and
savings, and various measures of the hash table size and chain
lengths.

     <p><a name="index-maint-print-target_002dstack-2343"></a><a name="index-target-stack-description-2344"></a><br><dt><code>maint print target-stack</code><dd>A <dfn>target</dfn> is an interface between the debugger and a particular
kind of file or process.  Targets can be stacked in <dfn>strata</dfn>,
so that more than one target can potentially respond to a request. 
In particular, memory accesses will walk down the stack of targets
until they find a target that is interested in handling that particular
address.

     <p>This command prints a short description of each layer that was pushed on
the <dfn>target stack</dfn>, starting from the top layer down to the bottom one.

     <p><a name="index-maint-print-type-2345"></a><a name="index-type-chain-of-a-data-type-2346"></a><br><dt><code>maint print type </code><var>expr</var><dd>Print the type chain for a type specified by <var>expr</var>.  The argument
can be either a type name or a symbol.  If it is a symbol, the type of
that symbol is described.  The type chain produced by this command is
a recursive definition of the data type as stored in <span class="sc">gdb</span>'s
data structures, including its flags and contained types.

     <p><a name="index-maint-set-dwarf2-always_002ddisassemble-2347"></a><a name="index-maint-show-dwarf2-always_002ddisassemble-2348"></a><br><dt><code>maint set dwarf2 always-disassemble</code><br><dt><code>maint show dwarf2 always-disassemble</code><dd>Control the behavior of <code>info address</code> when using DWARF debugging
information.

     <p>The default is <code>off</code>, which means that <span class="sc">gdb</span> should try to
describe a variable's location in an easily readable format.  When
<code>on</code>, <span class="sc">gdb</span> will instead display the DWARF location
expression in an assembly-like format.  Note that some locations are
too complex for <span class="sc">gdb</span> to describe simply; in this case you will
always see the disassembly form.

     <p>Here is an example of the resulting disassembly:

     <pre class="smallexample">          (gdb) info addr argc
          Symbol "argc" is a complex DWARF expression:
               1: DW_OP_fbreg 0
</pre>
     <p>For more information on these expressions, see
<a href="http://www.dwarfstd.org/">the DWARF standard</a>.

     <p><a name="index-maint-set-dwarf2-max_002dcache_002dage-2349"></a><a name="index-maint-show-dwarf2-max_002dcache_002dage-2350"></a><br><dt><code>maint set dwarf2 max-cache-age</code><dt><code>maint show dwarf2 max-cache-age</code><dd>Control the DWARF 2 compilation unit cache.

     <p><a name="index-DWARF-2-compilation-units-cache-2351"></a>In object files with inter-compilation-unit references, such as those
produced by the GCC option &lsquo;<samp><span class="samp">-feliminate-dwarf2-dups</span></samp>&rsquo;, the DWARF 2
reader needs to frequently refer to previously read compilation units. 
This setting controls how long a compilation unit will remain in the
cache if it is not referenced.  A higher limit means that cached
compilation units will be stored in memory longer, and more total
memory will be used.  Setting it to zero disables caching, which will
slow down <span class="sc">gdb</span> startup, but reduce memory consumption.

     <p><a name="index-maint-set-profile-2352"></a><a name="index-maint-show-profile-2353"></a><a name="index-profiling-GDB-2354"></a><br><dt><code>maint set profile</code><dt><code>maint show profile</code><dd>Control profiling of <span class="sc">gdb</span>.

     <p>Profiling will be disabled until you use the &lsquo;<samp><span class="samp">maint set profile</span></samp>&rsquo;
command to enable it.  When you enable profiling, the system will begin
collecting timing and execution count data; when you disable profiling or
exit <span class="sc">gdb</span>, the results will be written to a log file.  Remember that
if you use profiling, <span class="sc">gdb</span> will overwrite the profiling log file
(often called <samp><span class="file">gmon.out</span></samp>).  If you have a record of important profiling
data in a <samp><span class="file">gmon.out</span></samp> file, be sure to move it to a safe location.

     <p>Configuring with &lsquo;<samp><span class="samp">--enable-profiling</span></samp>&rsquo; arranges for <span class="sc">gdb</span> to be
compiled with the &lsquo;<samp><span class="samp">-pg</span></samp>&rsquo; compiler option.

     <p><a name="index-maint-set-show_002ddebug_002dregs-2355"></a><a name="index-maint-show-show_002ddebug_002dregs-2356"></a><a name="index-hardware-debug-registers-2357"></a><br><dt><code>maint set show-debug-regs</code><dt><code>maint show show-debug-regs</code><dd>Control whether to show variables that mirror the hardware debug
registers.  Use <code>ON</code> to enable, <code>OFF</code> to disable.  If
enabled, the debug registers values are shown when <span class="sc">gdb</span> inserts or
removes a hardware breakpoint or watchpoint, and when the inferior
triggers a hardware-assisted breakpoint or watchpoint.

     <p><a name="index-maint-set-show_002dall_002dtib-2358"></a><a name="index-maint-show-show_002dall_002dtib-2359"></a><br><dt><code>maint set show-all-tib</code><dt><code>maint show show-all-tib</code><dd>Control whether to show all non zero areas within a 1k block starting
at thread local base, when using the &lsquo;<samp><span class="samp">info w32 thread-information-block</span></samp>&rsquo;
command.

     <p><a name="index-maint-space-2360"></a><a name="index-memory-used-by-commands-2361"></a><br><dt><code>maint space</code><dd>Control whether to display memory usage for each command.  If set to a
nonzero value, <span class="sc">gdb</span> will display how much memory each command
took, following the command's own output.  This can also be requested
by invoking <span class="sc">gdb</span> with the <samp><span class="option">--statistics</span></samp> command-line
switch (see <a href="Mode-Options.html#Mode-Options">Mode Options</a>).

     <p><a name="index-maint-time-2362"></a><a name="index-time-of-command-execution-2363"></a><br><dt><code>maint time</code><dd>Control whether to display the execution time for each command.  If
set to a nonzero value, <span class="sc">gdb</span> will display how much time it
took to execute each command, following the command's own output. 
The time is not printed for the commands that run the target, since
there's no mechanism currently to compute how much time was spend
by <span class="sc">gdb</span> and how much time was spend by the program been debugged. 
it's not possibly currently
This can also be requested by invoking <span class="sc">gdb</span> with the
<samp><span class="option">--statistics</span></samp> command-line switch (see <a href="Mode-Options.html#Mode-Options">Mode Options</a>).

     <p><a name="index-maint-translate_002daddress-2364"></a><br><dt><code>maint translate-address </code><span class="roman">[</span><var>section</var><span class="roman">]</span> <var>addr</var><dd>Find the symbol stored at the location specified by the address
<var>addr</var> and an optional section name <var>section</var>.  If found,
<span class="sc">gdb</span> prints the name of the closest symbol and an offset from
the symbol's location to the specified address.  This is similar to
the <code>info address</code> command (see <a href="Symbols.html#Symbols">Symbols</a>), except that this
command also allows to find symbols in other sections.

     <p>If section was not specified, the section in which the symbol was found
is also printed.  For dynamically linked executables, the name of
executable or shared library containing the symbol is printed as well.

   </dl>

   <p>The following command is useful for non-interactive invocations of
<span class="sc">gdb</span>, such as in the test suite.

     <dl>
<dt><code>set watchdog </code><var>nsec</var><dd><a name="index-set-watchdog-2365"></a><a name="index-watchdog-timer-2366"></a><a name="index-timeout-for-commands-2367"></a>Set the maximum number of seconds <span class="sc">gdb</span> will wait for the
target operation to finish.  If this time expires, <span class="sc">gdb</span>
reports and error and the command is aborted.

     <br><dt><code>show watchdog</code><dd>Show the current setting of the target wait timeout. 
</dl>

   </body></html>