* Stack:: Examining the stack
* Source:: Examining source files
* Data:: Examining data
+* Tracepoints:: Debugging remote targets non-intrusively
* Languages:: Using @value{GDBN} with different languages
This file describes @value{GDBN}, the @sc{gnu} symbolic debugger.
-This is the @value{EDITION} Edition, @value{DATE}, for @value{GDBN} Version
+This is the @value{EDITION} Edition, @value{DATE}, for @value{GDBN} Version
@value{GDBVN}.
Copyright (C) 1988-2000 Free Software Foundation, Inc.
So that they may not regard their many labors as thankless, we
particularly thank those who shepherded @value{GDBN} through major
releases:
-Andrew Cagney (release 5.0);
+Andrew Cagney (releases 5.0 and 5.1);
Jim Blandy (release 4.18);
Jason Molenda (release 4.17);
Stan Shebs (release 4.14);
Richard Stallman, assisted at various times by Peter TerMaat, Chris
Hanson, and Richard Mlynarik, handled releases through 2.8.
-Michael Tiemann is the author of most of the @sc{gnu} C++ support in
-@value{GDBN}, with significant additional contributions from Per
-Bothner. James Clark wrote the @sc{gnu} C++ demangler. Early work on
-C++ was by Peter TerMaat (who also did much general update work leading
-to release 3.0).
+Michael Tiemann is the author of most of the @sc{gnu} C@t{++} support
+in @value{GDBN}, with significant additional contributions from Per
+Bothner and Daniel Berlin. James Clark wrote the @sc{gnu} C@t{++}
+demangler. Early work on C@t{++} was by Peter TerMaat (who also did
+much general update work leading to release 3.0).
-@value{GDBN} 4 uses the BFD subroutine library to examine multiple
+@value{GDBN} uses the BFD subroutine library to examine multiple
object-file formats; BFD was a joint project of David V.
Henkel-Wallace, Rich Pixley, Steve Chamberlain, and John Gilmore.
Modula-2 support, and contributed the Languages chapter of this manual.
Fred Fish wrote most of the support for Unix System Vr4.
-He also enhanced the command-completion support to cover C++ overloaded
+He also enhanced the command-completion support to cover C@t{++} overloaded
symbols.
Hitachi America, Ltd. sponsored the support for H8/300, H8/500, and
The following people at the Hewlett-Packard Company contributed
support for the PA-RISC 2.0 architecture, HP-UX 10.20, 10.30, and 11.0
-(narrow mode), HP's implementation of kernel threads, HP's aC++
+(narrow mode), HP's implementation of kernel threads, HP's aC@t{++}
compiler, and the terminal user interface: Ben Krepp, Richard Title,
John Bishop, Susan Macchia, Kathy Mann, Satish Pai, India Paul, Steve
Rehrauer, and Elena Zannoni. Kim Haase provided HP-specific
information in this manual.
+DJ Delorie ported @value{GDBN} to MS-DOS, for the DJGPP project.
+Robert Hoehne made significant contributions to the DJGPP port.
+
Cygnus Solutions has sponsored @value{GDBN} maintenance and much of its
development since 1991. Cygnus engineers who have worked on @value{GDBN}
fulltime include Mark Alexander, Jim Blandy, Per Bothner, Kevin
MS-DOS/MS-Windows supports this mode of operation, but the event loop is
suspended when the debuggee runs.}, so you don't need to wait for
control to return to @value{GDBN} before you type the next command.
-(@emph{Note:} as of version 5.0, the target side of the asynchronous
+(@emph{Note:} as of version 5.1, the target side of the asynchronous
operation is not yet in place, so @samp{-async} does not work fully
yet.)
@c FIXME: when the target side of the event loop is done, the above NOTE
command.
If you just want to see the list of alternatives in the first place, you
-can press @kbd{M-?} rather than pressing @key{TAB} twice. @kbd{M-?}
+can press @kbd{M-?} rather than pressing @key{TAB} twice. @kbd{M-?}
means @kbd{@key{META} ?}. You can type this either by holding down a
key designated as the @key{META} shift on your keyboard (if there is
one) while typing @kbd{?}, or as @key{ESC} followed by @kbd{?}.
@value{GDBN} commands.
The most likely situation where you might need this is in typing the
-name of a C++ function. This is because C++ allows function overloading
-(multiple definitions of the same function, distinguished by argument
-type). For example, when you want to set a breakpoint you may need to
-distinguish whether you mean the version of @code{name} that takes an
-@code{int} parameter, @code{name(int)}, or the version that takes a
-@code{float} parameter, @code{name(float)}. To use the word-completion
-facilities in this situation, type a single quote @code{'} at the
-beginning of the function name. This alerts @value{GDBN} that it may need to
-consider more information than usual when you press @key{TAB} or
-@kbd{M-?} to request word completion:
+name of a C@t{++} function. This is because C@t{++} allows function
+overloading (multiple definitions of the same function, distinguished
+by argument type). For example, when you want to set a breakpoint you
+may need to distinguish whether you mean the version of @code{name}
+that takes an @code{int} parameter, @code{name(int)}, or the version
+that takes a @code{float} parameter, @code{name(float)}. To use the
+word-completion facilities in this situation, type a single quote
+@code{'} at the beginning of the function name. This alerts
+@value{GDBN} that it may need to consider more information than usual
+when you press @key{TAB} or @kbd{M-?} to request word completion:
@example
(@value{GDBP}) b 'bubble( @kbd{M-?}
completion on an overloaded symbol.
For more information about overloaded functions, see @ref{C plus plus
-expressions, ,C++ expressions}. You can use the command @code{set
+expressions, ,C@t{++} expressions}. You can use the command @code{set
overload-resolution off} to disable overload resolution;
-see @ref{Debugging C plus plus, ,@value{GDBN} features for C++}.
+see @ref{Debugging C plus plus, ,@value{GDBN} features for C@t{++}}.
@node Help
apropos reload
@end smallexample
-@noindent results in:
+@noindent
+results in:
@smallexample
@c @group
@cindex catchpoints
@cindex breakpoint on events
A @dfn{catchpoint} is another special breakpoint that stops your program
-when a certain kind of event occurs, such as the throwing of a C++
+when a certain kind of event occurs, such as the throwing of a C@t{++}
exception or the loading of a library. As with watchpoints, you use a
different command to set a catchpoint (@pxref{Set Catchpoints, ,Setting
catchpoints}), but aside from that, you can manage a catchpoint like any
@item break @var{function}
Set a breakpoint at entry to function @var{function}.
When using source languages that permit overloading of symbols, such as
-C++, @var{function} may refer to more than one possible place to break.
+C@t{++}, @var{function} may refer to more than one possible place to break.
@xref{Breakpoint Menus,,Breakpoint menus}, for a discussion of that situation.
@item break +@var{offset}
@code{.*} leading and trailing the regular expression you supply, so to
match only functions that begin with @code{foo}, use @code{^foo}.
-When debugging C++ programs, @code{rbreak} is useful for setting
+When debugging C@t{++} programs, @code{rbreak} is useful for setting
breakpoints on overloaded functions that are not members of any special
classes.
@cindex event handling
You can use @dfn{catchpoints} to cause the debugger to stop for certain
-kinds of program events, such as C++ exceptions or the loading of a
+kinds of program events, such as C@t{++} exceptions or the loading of a
shared library. Use the @code{catch} command to set a catchpoint.
@table @code
@table @code
@item throw
@kindex catch throw
-The throwing of a C++ exception.
+The throwing of a C@t{++} exception.
@item catch
@kindex catch catch
-The catching of a C++ exception.
+The catching of a C@t{++} exception.
@item exec
@kindex catch exec
Use the @code{info break} command to list the current catchpoints.
-There are currently some limitations to C++ exception handling
+There are currently some limitations to C@t{++} exception handling
(@code{catch throw} and @code{catch catch}) in @value{GDBN}:
@itemize @bullet
out where the exception was raised.
To stop just before an exception handler is called, you need some
-knowledge of the implementation. In the case of @sc{gnu} C++, exceptions are
+knowledge of the implementation. In the case of @sc{gnu} C@t{++}, exceptions are
raised by calling a library function named @code{__raise_exception}
which has the following ANSI C interface:
@cindex overloading
@cindex symbol overloading
-Some programming languages (notably C++) permit a single function name
+Some programming languages (notably C@t{++}) permit a single function name
to be defined several times, for application in different contexts.
This is called @dfn{overloading}. When a function name is overloaded,
@samp{break @var{function}} is not enough to tell @value{GDBN} where you want
(@value{GDBP}) p 'f2.c'::x
@end example
-@cindex C++ scope resolution
+@cindex C@t{++} scope resolution
This use of @samp{::} is very rarely in conflict with the very similar
-use of the same notation in C++. @value{GDBN} also supports use of the C++
+use of the same notation in C@t{++}. @value{GDBN} also supports use of the C@t{++}
scope resolution operator in @value{GDBN} expressions.
@c FIXME: Um, so what happens in one of those rare cases where it's in
@c conflict?? --mew
To solve such problems, either recompile without optimizations, or use a
different debug info format, if the compiler supports several such
-formats. For example, @value{NGCC}, the @sc{gnu} C/C++ compiler usually
+formats. For example, @value{NGCC}, the @sc{gnu} C/C@t{++} compiler usually
supports the @samp{-gstabs} option. @samp{-gstabs} produces debug info
in a format that is superior to formats such as COFF. You may be able
to use DWARF2 (@samp{-gdwarf-2}), which is also an effective form for
@need 1000
@noindent
-These settings are of interest when debugging C++ programs:
+These settings are of interest when debugging C@t{++} programs:
@table @code
@cindex demangling
@kindex set print demangle
@item set print demangle
@itemx set print demangle on
-Print C++ names in their source form rather than in the encoded
+Print C@t{++} names in their source form rather than in the encoded
(``mangled'') form passed to the assembler and linker for type-safe
linkage. The default is on.
@kindex show print demangle
@item show print demangle
-Show whether C++ names are printed in mangled or demangled form.
+Show whether C@t{++} names are printed in mangled or demangled form.
@kindex set print asm-demangle
@item set print asm-demangle
@itemx set print asm-demangle on
-Print C++ names in their source form rather than their mangled form, even
+Print C@t{++} names in their source form rather than their mangled form, even
in assembler code printouts such as instruction disassemblies.
The default is off.
@kindex show print asm-demangle
@item show print asm-demangle
-Show whether C++ names in assembly listings are printed in mangled
+Show whether C@t{++} names in assembly listings are printed in mangled
or demangled form.
@kindex set demangle-style
-@cindex C++ symbol decoding style
-@cindex symbol decoding style, C++
+@cindex C@t{++} symbol decoding style
+@cindex symbol decoding style, C@t{++}
@item set demangle-style @var{style}
Choose among several encoding schemes used by different compilers to
-represent C++ names. The choices for @var{style} are currently:
+represent C@t{++} names. The choices for @var{style} are currently:
@table @code
@item auto
Allow @value{GDBN} to choose a decoding style by inspecting your program.
@item gnu
-Decode based on the @sc{gnu} C++ compiler (@code{g++}) encoding algorithm.
+Decode based on the @sc{gnu} C@t{++} compiler (@code{g++}) encoding algorithm.
This is the default.
@item hp
-Decode based on the HP ANSI C++ (@code{aCC}) encoding algorithm.
+Decode based on the HP ANSI C@t{++} (@code{aCC}) encoding algorithm.
@item lucid
-Decode based on the Lucid C++ compiler (@code{lcc}) encoding algorithm.
+Decode based on the Lucid C@t{++} compiler (@code{lcc}) encoding algorithm.
@item arm
-Decode using the algorithm in the @cite{C++ Annotated Reference Manual}.
+Decode using the algorithm in the @cite{C@t{++} Annotated Reference Manual}.
@strong{Warning:} this setting alone is not sufficient to allow
debugging @code{cfront}-generated executables. @value{GDBN} would
require further enhancement to permit that.
@kindex show demangle-style
@item show demangle-style
-Display the encoding style currently in use for decoding C++ symbols.
+Display the encoding style currently in use for decoding C@t{++} symbols.
@kindex set print object
@item set print object
@kindex set print static-members
@item set print static-members
@itemx set print static-members on
-Print static members when displaying a C++ object. The default is on.
+Print static members when displaying a C@t{++} object. The default is on.
@item set print static-members off
-Do not print static members when displaying a C++ object.
+Do not print static members when displaying a C@t{++} object.
@kindex show print static-members
@item show print static-members
-Show whether C++ static members are printed, or not.
+Show whether C@t{++} static members are printed, or not.
@c These don't work with HP ANSI C++ yet.
@kindex set print vtbl
@item set print vtbl
@itemx set print vtbl on
-Pretty print C++ virtual function tables. The default is off.
+Pretty print C@t{++} virtual function tables. The default is off.
(The @code{vtbl} commands do not work on programs compiled with the HP
-ANSI C++ compiler (@code{aCC}).)
+ANSI C@t{++} compiler (@code{aCC}).)
@item set print vtbl off
-Do not pretty print C++ virtual function tables.
+Do not pretty print C@t{++} virtual function tables.
@kindex show print vtbl
@item show print vtbl
-Show whether C++ virtual function tables are pretty printed, or not.
+Show whether C@t{++} virtual function tables are pretty printed, or not.
@end table
@node Value History
@c @item noverify (default)
@c @end table
+@node Tracepoints
+@chapter Tracepoints
+@c This chapter is based on the documentation written by Michael
+@c Snyder, David Taylor, Jim Blandy, and Elena Zannoni.
+
+@cindex tracepoints
+In some applications, it is not feasible for the debugger to interrupt
+the program's execution long enough for the developer to learn
+anything helpful about its behavior. If the program's correctness
+depends on its real-time behavior, delays introduced by a debugger
+might cause the program to change its behavior drastically, or perhaps
+fail, even when the code itself is correct. It is useful to be able
+to observe the program's behavior without interrupting it.
+
+Using @value{GDBN}'s @code{trace} and @code{collect} commands, you can
+specify locations in the program, called @dfn{tracepoints}, and
+arbitrary expressions to evaluate when those tracepoints are reached.
+Later, using the @code{tfind} command, you can examine the values
+those expressions had when the program hit the tracepoints. The
+expressions may also denote objects in memory---structures or arrays,
+for example---whose values @value{GDBN} should record; while visiting
+a particular tracepoint, you may inspect those objects as if they were
+in memory at that moment. However, because @value{GDBN} records these
+values without interacting with you, it can do so quickly and
+unobtrusively, hopefully not disturbing the program's behavior.
+
+The tracepoint facility is currently available only for remote
+targets. @xref{Targets}.
+
+This chapter describes the tracepoint commands and features.
+
+@menu
+* Set Tracepoints::
+* Analyze Collected Data::
+* Tracepoint Variables::
+@end menu
+
+@node Set Tracepoints
+@section Commands to Set Tracepoints
+
+Before running such a @dfn{trace experiment}, an arbitrary number of
+tracepoints can be set. Like a breakpoint (@pxref{Set Breaks}), a
+tracepoint has a number assigned to it by @value{GDBN}. Like with
+breakpoints, tracepoint numbers are successive integers starting from
+one. Many of the commands associated with tracepoints take the
+tracepoint number as their argument, to identify which tracepoint to
+work on.
+
+For each tracepoint, you can specify, in advance, some arbitrary set
+of data that you want the target to collect in the trace buffer when
+it hits that tracepoint. The collected data can include registers,
+local variables, or global data. Later, you can use @value{GDBN}
+commands to examine the values these data had at the time the
+tracepoint was hit.
+
+This section describes commands to set tracepoints and associated
+conditions and actions.
+
+@menu
+* Create and Delete Tracepoints::
+* Enable and Disable Tracepoints::
+* Tracepoint Passcounts::
+* Tracepoint Actions::
+* Listing Tracepoints::
+* Starting and Stopping Trace Experiment::
+@end menu
+
+@node Create and Delete Tracepoints
+@subsection Create and Delete Tracepoints
+
+@table @code
+@cindex set tracepoint
+@kindex trace
+@item trace
+The @code{trace} command is very similar to the @code{break} command.
+Its argument can be a source line, a function name, or an address in
+the target program. @xref{Set Breaks}. The @code{trace} command
+defines a tracepoint, which is a point in the target program where the
+debugger will briefly stop, collect some data, and then allow the
+program to continue. Setting a tracepoint or changing its commands
+doesn't take effect until the next @code{tstart} command; thus, you
+cannot change the tracepoint attributes once a trace experiment is
+running.
+
+Here are some examples of using the @code{trace} command:
+
+@smallexample
+(@value{GDBP}) @b{trace foo.c:121} // a source file and line number
+
+(@value{GDBP}) @b{trace +2} // 2 lines forward
+
+(@value{GDBP}) @b{trace my_function} // first source line of function
+
+(@value{GDBP}) @b{trace *my_function} // EXACT start address of function
+
+(@value{GDBP}) @b{trace *0x2117c4} // an address
+@end smallexample
+
+@noindent
+You can abbreviate @code{trace} as @code{tr}.
+
+@vindex $tpnum
+@cindex last tracepoint number
+@cindex recent tracepoint number
+@cindex tracepoint number
+The convenience variable @code{$tpnum} records the tracepoint number
+of the most recently set tracepoint.
+
+@kindex delete tracepoint
+@cindex tracepoint deletion
+@item delete tracepoint @r{[}@var{num}@r{]}
+Permanently delete one or more tracepoints. With no argument, the
+default is to delete all tracepoints.
+
+Examples:
+
+@smallexample
+(@value{GDBP}) @b{delete trace 1 2 3} // remove three tracepoints
+
+(@value{GDBP}) @b{delete trace} // remove all tracepoints
+@end smallexample
+
+@noindent
+You can abbreviate this command as @code{del tr}.
+@end table
+
+@node Enable and Disable Tracepoints
+@subsection Enable and Disable Tracepoints
+
+@table @code
+@kindex disable tracepoint
+@item disable tracepoint @r{[}@var{num}@r{]}
+Disable tracepoint @var{num}, or all tracepoints if no argument
+@var{num} is given. A disabled tracepoint will have no effect during
+the next trace experiment, but it is not forgotten. You can re-enable
+a disabled tracepoint using the @code{enable tracepoint} command.
+
+@kindex enable tracepoint
+@item enable tracepoint @r{[}@var{num}@r{]}
+Enable tracepoint @var{num}, or all tracepoints. The enabled
+tracepoints will become effective the next time a trace experiment is
+run.
+@end table
+
+@node Tracepoint Passcounts
+@subsection Tracepoint Passcounts
+
+@table @code
+@kindex passcount
+@cindex tracepoint pass count
+@item passcount @r{[}@var{n} @r{[}@var{num}@r{]]}
+Set the @dfn{passcount} of a tracepoint. The passcount is a way to
+automatically stop a trace experiment. If a tracepoint's passcount is
+@var{n}, then the trace experiment will be automatically stopped on
+the @var{n}'th time that tracepoint is hit. If the tracepoint number
+@var{num} is not specified, the @code{passcount} command sets the
+passcount of the most recently defined tracepoint. If no passcount is
+given, the trace experiment will run until stopped explicitly by the
+user.
+
+Examples:
+
+@smallexample
+(@value{GDBP}) @b{passcount 5 2} // Stop on the 5th execution of tracepoint 2
+
+(@value{GDBP}) @b{passcount 12} // Stop on the 12th execution of the
+ // most recently defined tracepoint.
+(@value{GDBP}) @b{trace foo}
+(@value{GDBP}) @b{pass 3}
+(@value{GDBP}) @b{trace bar}
+(@value{GDBP}) @b{pass 2}
+(@value{GDBP}) @b{trace baz}
+(@value{GDBP}) @b{pass 1} // Stop tracing when foo has been
+ // executed 3 times OR when bar has
+ // been executed 2 times
+ // OR when baz has been executed 1 time.
+@end smallexample
+@end table
+
+@node Tracepoint Actions
+@subsection Tracepoint Action Lists
+
+@table @code
+@kindex actions
+@cindex tracepoint actions
+@item actions @r{[}@var{num}@r{]}
+This command will prompt for a list of actions to be taken when the
+tracepoint is hit. If the tracepoint number @var{num} is not
+specified, this command sets the actions for the one that was most
+recently defined (so that you can define a tracepoint and then say
+@code{actions} without bothering about its number). You specify the
+actions themselves on the following lines, one action at a time, and
+terminate the actions list with a line containing just @code{end}. So
+far, the only defined actions are @code{collect} and
+@code{while-stepping}.
+
+@cindex remove actions from a tracepoint
+To remove all actions from a tracepoint, type @samp{actions @var{num}}
+and follow it immediately with @samp{end}.
+
+@smallexample
+(@value{GDBP}) @b{collect @var{data}} // collect some data
+
+(@value{GDBP}) @b{while-stepping 5} // single-step 5 times and collect data
+
+(@value{GDBP}) @b{end} // signals the end of actions.
+@end smallexample
+
+In the following example, the action list begins with @code{collect}
+commands indicating the things to be collected when the tracepoint is
+hit. Then, in order to single-step and collect additional data
+following the tracepoint, a @code{while-stepping} command is used,
+followed by the list of things to be collected while stepping. The
+@code{while-stepping} command is terminated by its own separate
+@code{end} command. Lastly, the action list is terminated by an
+@code{end} command.
+
+@smallexample
+(@value{GDBP}) @b{trace foo}
+(@value{GDBP}) @b{actions}
+Enter actions for tracepoint 1, one per line:
+> collect bar,baz
+> collect $regs
+> while-stepping 12
+ > collect $fp, $sp
+ > end
+end
+@end smallexample
+
+@kindex collect @r{(tracepoints)}
+@item collect @var{expr1}, @var{expr2}, @dots{}
+Collect values of the given expressions when the tracepoint is hit.
+This command accepts a comma-separated list of any valid expressions.
+In addition to global, static, or local variables, the following
+special arguments are supported:
+
+@table @code
+@item $regs
+collect all registers
+
+@item $args
+collect all function arguments
+
+@item $locals
+collect all local variables.
+@end table
+
+You can give several consecutive @code{collect} commands, each one
+with a single argument, or one @code{collect} command with several
+arguments separated by commas: the effect is the same.
+
+@kindex while-stepping @r{(tracepoints)}
+@item while-stepping @var{n}
+Perform @var{n} single-step traces after the tracepoint, collecting
+new data at each step. The @code{while-stepping} command is
+followed by the list of what to collect while stepping (followed by
+its own @code{end} command):
+
+@smallexample
+> while-stepping 12
+ > collect $regs, myglobal
+ > end
+>
+@end smallexample
+
+@noindent
+You may abbreviate @code{while-stepping} as @code{ws} or
+@code{stepping}.
+@end table
+
+@node Listing Tracepoints
+@subsection Listing Tracepoints
+
+@table @code
+@kindex info tracepoints
+@cindex information about tracepoints
+@item info tracepoints @r{[}@var{num}@r{]}
+Display information the tracepoint @var{num}. If you don't specify a
+tracepoint number displays information about all the tracepoints
+defined so far. For each tracepoint, the following information is
+shown:
+
+@itemize @bullet
+@item
+its number
+@item
+whether it is enabled or disabled
+@item
+its address
+@item
+its passcount as given by the @code{passcount @var{n}} command
+@item
+its step count as given by the @code{while-stepping @var{n}} command
+@item
+where in the source files is the tracepoint set
+@item
+its action list as given by the @code{actions} command
+@end itemize
+
+@smallexample
+(@value{GDBP}) @b{info trace}
+Num Enb Address PassC StepC What
+1 y 0x002117c4 0 0 <gdb_asm>
+2 y 0x0020dc64 0 0 in gdb_test at gdb_test.c:375
+3 y 0x0020b1f4 0 0 in collect_data at ../foo.c:1741
+(@value{GDBP})
+@end smallexample
+
+@noindent
+This command can be abbreviated @code{info tp}.
+@end table
+
+@node Starting and Stopping Trace Experiment
+@subsection Starting and Stopping Trace Experiment
+
+@table @code
+@kindex tstart
+@cindex start a new trace experiment
+@cindex collected data discarded
+@item tstart
+This command takes no arguments. It starts the trace experiment, and
+begins collecting data. This has the side effect of discarding all
+the data collected in the trace buffer during the previous trace
+experiment.
+
+@kindex tstop
+@cindex stop a running trace experiment
+@item tstop
+This command takes no arguments. It ends the trace experiment, and
+stops collecting data.
+
+@strong{Note:} a trace experiment and data collection may stop
+automatically if any tracepoint's passcount is reached
+(@pxref{Tracepoint Passcounts}), or if the trace buffer becomes full.
+
+@kindex tstatus
+@cindex status of trace data collection
+@cindex trace experiment, status of
+@item tstatus
+This command displays the status of the current trace data
+collection.
+@end table
+
+Here is an example of the commands we described so far:
+
+@smallexample
+(@value{GDBP}) @b{trace gdb_c_test}
+(@value{GDBP}) @b{actions}
+Enter actions for tracepoint #1, one per line.
+> collect $regs,$locals,$args
+> while-stepping 11
+ > collect $regs
+ > end
+> end
+(@value{GDBP}) @b{tstart}
+ [time passes @dots{}]
+(@value{GDBP}) @b{tstop}
+@end smallexample
+
+
+@node Analyze Collected Data
+@section Using the collected data
+
+After the tracepoint experiment ends, you use @value{GDBN} commands
+for examining the trace data. The basic idea is that each tracepoint
+collects a trace @dfn{snapshot} every time it is hit and another
+snapshot every time it single-steps. All these snapshots are
+consecutively numbered from zero and go into a buffer, and you can
+examine them later. The way you examine them is to @dfn{focus} on a
+specific trace snapshot. When the remote stub is focused on a trace
+snapshot, it will respond to all @value{GDBN} requests for memory and
+registers by reading from the buffer which belongs to that snapshot,
+rather than from @emph{real} memory or registers of the program being
+debugged. This means that @strong{all} @value{GDBN} commands
+(@code{print}, @code{info registers}, @code{backtrace}, etc.) will
+behave as if we were currently debugging the program state as it was
+when the tracepoint occurred. Any requests for data that are not in
+the buffer will fail.
+
+@menu
+* tfind:: How to select a trace snapshot
+* tdump:: How to display all data for a snapshot
+* save-tracepoints:: How to save tracepoints for a future run
+@end menu
+
+@node tfind
+@subsection @code{tfind @var{n}}
+
+@kindex tfind
+@cindex select trace snapshot
+@cindex find trace snapshot
+The basic command for selecting a trace snapshot from the buffer is
+@code{tfind @var{n}}, which finds trace snapshot number @var{n},
+counting from zero. If no argument @var{n} is given, the next
+snapshot is selected.
+
+Here are the various forms of using the @code{tfind} command.
+
+@table @code
+@item tfind start
+Find the first snapshot in the buffer. This is a synonym for
+@code{tfind 0} (since 0 is the number of the first snapshot).
+
+@item tfind none
+Stop debugging trace snapshots, resume @emph{live} debugging.
+
+@item tfind end
+Same as @samp{tfind none}.
+
+@item tfind
+No argument means find the next trace snapshot.
+
+@item tfind -
+Find the previous trace snapshot before the current one. This permits
+retracing earlier steps.
+
+@item tfind tracepoint @var{num}
+Find the next snapshot associated with tracepoint @var{num}. Search
+proceeds forward from the last examined trace snapshot. If no
+argument @var{num} is given, it means find the next snapshot collected
+for the same tracepoint as the current snapshot.
+
+@item tfind pc @var{addr}
+Find the next snapshot associated with the value @var{addr} of the
+program counter. Search proceeds forward from the last examined trace
+snapshot. If no argument @var{addr} is given, it means find the next
+snapshot with the same value of PC as the current snapshot.
+
+@item tfind outside @var{addr1}, @var{addr2}
+Find the next snapshot whose PC is outside the given range of
+addresses.
+
+@item tfind range @var{addr1}, @var{addr2}
+Find the next snapshot whose PC is between @var{addr1} and
+@var{addr2}. @c FIXME: Is the range inclusive or exclusive?
+
+@item tfind line @r{[}@var{file}:@r{]}@var{n}
+Find the next snapshot associated with the source line @var{n}. If
+the optional argument @var{file} is given, refer to line @var{n} in
+that source file. Search proceeds forward from the last examined
+trace snapshot. If no argument @var{n} is given, it means find the
+next line other than the one currently being examined; thus saying
+@code{tfind line} repeatedly can appear to have the same effect as
+stepping from line to line in a @emph{live} debugging session.
+@end table
+
+The default arguments for the @code{tfind} commands are specifically
+designed to make it easy to scan through the trace buffer. For
+instance, @code{tfind} with no argument selects the next trace
+snapshot, and @code{tfind -} with no argument selects the previous
+trace snapshot. So, by giving one @code{tfind} command, and then
+simply hitting @key{RET} repeatedly you can examine all the trace
+snapshots in order. Or, by saying @code{tfind -} and then hitting
+@key{RET} repeatedly you can examine the snapshots in reverse order.
+The @code{tfind line} command with no argument selects the snapshot
+for the next source line executed. The @code{tfind pc} command with
+no argument selects the next snapshot with the same program counter
+(PC) as the current frame. The @code{tfind tracepoint} command with
+no argument selects the next trace snapshot collected by the same
+tracepoint as the current one.
+
+In addition to letting you scan through the trace buffer manually,
+these commands make it easy to construct @value{GDBN} scripts that
+scan through the trace buffer and print out whatever collected data
+you are interested in. Thus, if we want to examine the PC, FP, and SP
+registers from each trace frame in the buffer, we can say this:
+
+@smallexample
+(@value{GDBP}) @b{tfind start}
+(@value{GDBP}) @b{while ($trace_frame != -1)}
+> printf "Frame %d, PC = %08X, SP = %08X, FP = %08X\n", \
+ $trace_frame, $pc, $sp, $fp
+> tfind
+> end
+
+Frame 0, PC = 0020DC64, SP = 0030BF3C, FP = 0030BF44
+Frame 1, PC = 0020DC6C, SP = 0030BF38, FP = 0030BF44
+Frame 2, PC = 0020DC70, SP = 0030BF34, FP = 0030BF44
+Frame 3, PC = 0020DC74, SP = 0030BF30, FP = 0030BF44
+Frame 4, PC = 0020DC78, SP = 0030BF2C, FP = 0030BF44
+Frame 5, PC = 0020DC7C, SP = 0030BF28, FP = 0030BF44
+Frame 6, PC = 0020DC80, SP = 0030BF24, FP = 0030BF44
+Frame 7, PC = 0020DC84, SP = 0030BF20, FP = 0030BF44
+Frame 8, PC = 0020DC88, SP = 0030BF1C, FP = 0030BF44
+Frame 9, PC = 0020DC8E, SP = 0030BF18, FP = 0030BF44
+Frame 10, PC = 00203F6C, SP = 0030BE3C, FP = 0030BF14
+@end smallexample
+
+Or, if we want to examine the variable @code{X} at each source line in
+the buffer:
+
+@smallexample
+(@value{GDBP}) @b{tfind start}
+(@value{GDBP}) @b{while ($trace_frame != -1)}
+> printf "Frame %d, X == %d\n", $trace_frame, X
+> tfind line
+> end
+
+Frame 0, X = 1
+Frame 7, X = 2
+Frame 13, X = 255
+@end smallexample
+
+@node tdump
+@subsection @code{tdump}
+@kindex tdump
+@cindex dump all data collected at tracepoint
+@cindex tracepoint data, display
+
+This command takes no arguments. It prints all the data collected at
+the current trace snapshot.
+
+@smallexample
+(@value{GDBP}) @b{trace 444}
+(@value{GDBP}) @b{actions}
+Enter actions for tracepoint #2, one per line:
+> collect $regs, $locals, $args, gdb_long_test
+> end
+
+(@value{GDBP}) @b{tstart}
+
+(@value{GDBP}) @b{tfind line 444}
+#0 gdb_test (p1=0x11, p2=0x22, p3=0x33, p4=0x44, p5=0x55, p6=0x66)
+at gdb_test.c:444
+444 printp( "%s: arguments = 0x%X 0x%X 0x%X 0x%X 0x%X 0x%X\n", )
+
+(@value{GDBP}) @b{tdump}
+Data collected at tracepoint 2, trace frame 1:
+d0 0xc4aa0085 -995491707
+d1 0x18 24
+d2 0x80 128
+d3 0x33 51
+d4 0x71aea3d 119204413
+d5 0x22 34
+d6 0xe0 224
+d7 0x380035 3670069
+a0 0x19e24a 1696330
+a1 0x3000668 50333288
+a2 0x100 256
+a3 0x322000 3284992
+a4 0x3000698 50333336
+a5 0x1ad3cc 1758156
+fp 0x30bf3c 0x30bf3c
+sp 0x30bf34 0x30bf34
+ps 0x0 0
+pc 0x20b2c8 0x20b2c8
+fpcontrol 0x0 0
+fpstatus 0x0 0
+fpiaddr 0x0 0
+p = 0x20e5b4 "gdb-test"
+p1 = (void *) 0x11
+p2 = (void *) 0x22
+p3 = (void *) 0x33
+p4 = (void *) 0x44
+p5 = (void *) 0x55
+p6 = (void *) 0x66
+gdb_long_test = 17 '\021'
+
+(@value{GDBP})
+@end smallexample
+
+@node save-tracepoints
+@subsection @code{save-tracepoints @var{filename}}
+@kindex save-tracepoints
+@cindex save tracepoints for future sessions
+
+This command saves all current tracepoint definitions together with
+their actions and passcounts, into a file @file{@var{filename}}
+suitable for use in a later debugging session. To read the saved
+tracepoint definitions, use the @code{source} command (@pxref{Command
+Files}).
+
+@node Tracepoint Variables
+@section Convenience Variables for Tracepoints
+@cindex tracepoint variables
+@cindex convenience variables for tracepoints
+
+@table @code
+@vindex $trace_frame
+@item (int) $trace_frame
+The current trace snapshot (a.k.a.@: @dfn{frame}) number, or -1 if no
+snapshot is selected.
+
+@vindex $tracepoint
+@item (int) $tracepoint
+The tracepoint for the current trace snapshot.
+
+@vindex $trace_line
+@item (int) $trace_line
+The line number for the current trace snapshot.
+
+@vindex $trace_file
+@item (char []) $trace_file
+The source file for the current trace snapshot.
+
+@vindex $trace_func
+@item (char []) $trace_func
+The name of the function containing @code{$tracepoint}.
+@end table
+
+Note: @code{$trace_file} is not suitable for use in @code{printf},
+use @code{output} instead.
+
+Here's a simple example of using these convenience variables for
+stepping through all the trace snapshots and printing some of their
+data.
+
+@smallexample
+(@value{GDBP}) @b{tfind start}
+
+(@value{GDBP}) @b{while $trace_frame != -1}
+> output $trace_file
+> printf ", line %d (tracepoint #%d)\n", $trace_line, $tracepoint
+> tfind
+> end
+@end smallexample
+
@node Languages
@chapter Using @value{GDBN} with Different Languages
@cindex languages
file formats, the compiler might indicate which language a particular
source file is in. However, most of the time @value{GDBN} infers the
language from the name of the file. The language of a source file
-controls whether C++ names are demangled---this way @code{backtrace} can
+controls whether C@t{++} names are demangled---this way @code{backtrace} can
show each frame appropriately for its own language. There is no way to
set the language of a source file from within @value{GDBN}, but you can
set the language associated with a filename extension. @xref{Show, ,
@itemx .cpp
@itemx .cxx
@itemx .c++
-C++ source file
+C@t{++} source file
@item .f
@itemx .F
@node Support
@section Supported languages
-@value{GDBN} supports C, C++, Fortran, Java, Chill, assembly, and Modula-2.
+@value{GDBN} supports C, C@t{++}, Fortran, Java, Chill, assembly, and Modula-2.
@c This is false ...
Some @value{GDBN} features may be used in expressions regardless of the
language you use: the @value{GDBN} @code{@@} and @code{::} operators,
language reference or tutorial.
@menu
-* C:: C and C++
+* C:: C and C@t{++}
* Modula-2:: Modula-2
* Chill:: Chill
@end menu
@node C
-@subsection C and C++
+@subsection C and C@t{++}
-@cindex C and C++
-@cindex expressions in C or C++
+@cindex C and C@t{++}
+@cindex expressions in C or C@t{++}
-Since C and C++ are so closely related, many features of @value{GDBN} apply
+Since C and C@t{++} are so closely related, many features of @value{GDBN} apply
to both languages. Whenever this is the case, we discuss those languages
together.
@cindex C@t{++}
@cindex @code{g++}, @sc{gnu} C@t{++} compiler
-@cindex @sc{gnu} C++
-The C++ debugging facilities are jointly implemented by the C++
-compiler and @value{GDBN}. Therefore, to debug your C++ code
-effectively, you must compile your C++ programs with a supported
-C++ compiler, such as @sc{gnu} @code{g++}, or the HP ANSI C++
+@cindex @sc{gnu} C@t{++}
+The C@t{++} debugging facilities are jointly implemented by the C@t{++}
+compiler and @value{GDBN}. Therefore, to debug your C@t{++} code
+effectively, you must compile your C@t{++} programs with a supported
+C@t{++} compiler, such as @sc{gnu} @code{g++}, or the HP ANSI C@t{++}
compiler (@code{aCC}).
-For best results when using @sc{gnu} C++, use the stabs debugging
+For best results when using @sc{gnu} C@t{++}, use the stabs debugging
format. You can select that format explicitly with the @code{g++}
command-line options @samp{-gstabs} or @samp{-gstabs+}. See
@ref{Debugging Options,,Options for Debugging Your Program or @sc{gnu}
CC, gcc.info, Using @sc{gnu} CC}, for more information.
@menu
-* C Operators:: C and C++ operators
-* C Constants:: C and C++ constants
-* C plus plus expressions:: C++ expressions
-* C Defaults:: Default settings for C and C++
-* C Checks:: C and C++ type and range checks
+* C Operators:: C and C@t{++} operators
+* C Constants:: C and C@t{++} constants
+* C plus plus expressions:: C@t{++} expressions
+* C Defaults:: Default settings for C and C@t{++}
+* C Checks:: C and C@t{++} type and range checks
* Debugging C:: @value{GDBN} and C
-* Debugging C plus plus:: @value{GDBN} features for C++
+* Debugging C plus plus:: @value{GDBN} features for C@t{++}
@end menu
@node C Operators
-@subsubsection C and C++ operators
+@subsubsection C and C@t{++} operators
-@cindex C and C++ operators
+@cindex C and C@t{++} operators
Operators must be defined on values of specific types. For instance,
@code{+} is defined on numbers, but not on structures. Operators are
often defined on groups of types.
-For the purposes of C and C++, the following definitions hold:
+For the purposes of C and C@t{++}, the following definitions hold:
@itemize @bullet
@item
@emph{Integral types} include @code{int} with any of its storage-class
-specifiers; @code{char}; @code{enum}; and, for C++, @code{bool}.
+specifiers; @code{char}; @code{enum}; and, for C@t{++}, @code{bool}.
@item
@emph{Floating-point types} include @code{float}, @code{double}, and
@item &
Address operator. Defined on variables. Same precedence as @code{++}.
-For debugging C++, @value{GDBN} implements a use of @samp{&} beyond what is
-allowed in the C++ language itself: you can use @samp{&(&@var{ref})}
+For debugging C@t{++}, @value{GDBN} implements a use of @samp{&} beyond what is
+allowed in the C@t{++} language itself: you can use @samp{&(&@var{ref})}
(or, if you prefer, simply @samp{&&@var{ref}}) to examine the address
-where a C++ reference variable (declared with @samp{&@var{ref}}) is
+where a C@t{++} reference variable (declared with @samp{&@var{ref}}) is
stored.
@item -
Function parameter list. Same precedence as @code{->}.
@item ::
-C++ scope resolution operator. Defined on @code{struct}, @code{union},
+C@t{++} scope resolution operator. Defined on @code{struct}, @code{union},
and @code{class} types.
@item ::
@end menu
@node C Constants
-@subsubsection C and C++ constants
+@subsubsection C and C@t{++} constants
-@cindex C and C++ constants
+@cindex C and C@t{++} constants
-@value{GDBN} allows you to express the constants of C and C++ in the
+@value{GDBN} allows you to express the constants of C and C@t{++} in the
following ways:
@itemize @bullet
@end menu
@node C plus plus expressions
-@subsubsection C++ expressions
-
-@cindex expressions in C++
-@value{GDBN} expression handling can interpret most C++ expressions.
-
-@cindex C++ support, not in @sc{coff}
-@cindex @sc{coff} versus C++
-@cindex C++ and object formats
-@cindex object formats and C++
-@cindex a.out and C++
-@cindex @sc{ecoff} and C++
-@cindex @sc{xcoff} and C++
-@cindex @sc{elf}/stabs and C++
-@cindex @sc{elf}/@sc{dwarf} and C++
+@subsubsection C@t{++} expressions
+
+@cindex expressions in C@t{++}
+@value{GDBN} expression handling can interpret most C@t{++} expressions.
+
+@cindex C@t{++} support, not in @sc{coff}
+@cindex @sc{coff} versus C@t{++}
+@cindex C@t{++} and object formats
+@cindex object formats and C@t{++}
+@cindex a.out and C@t{++}
+@cindex @sc{ecoff} and C@t{++}
+@cindex @sc{xcoff} and C@t{++}
+@cindex @sc{elf}/stabs and C@t{++}
+@cindex @sc{elf}/@sc{dwarf} and C@t{++}
@c FIXME!! GDB may eventually be able to debug C++ using DWARF; check
@c periodically whether this has happened...
@quotation
-@emph{Warning:} @value{GDBN} can only debug C++ code if you use the
-proper compiler. Typically, C++ debugging depends on the use of
+@emph{Warning:} @value{GDBN} can only debug C@t{++} code if you use the
+proper compiler. Typically, C@t{++} debugging depends on the use of
additional debugging information in the symbol table, and thus requires
special support. In particular, if your compiler generates a.out, MIPS
@sc{ecoff}, RS/6000 @sc{xcoff}, or @sc{elf} with stabs extensions to the
symbol table, these facilities are all available. (With @sc{gnu} CC,
you can use the @samp{-gstabs} option to request stabs debugging
extensions explicitly.) Where the object code format is standard
-@sc{coff} or @sc{dwarf} in @sc{elf}, on the other hand, most of the C++
+@sc{coff} or @sc{dwarf} in @sc{elf}, on the other hand, most of the C@t{++}
support in @value{GDBN} does @emph{not} work.
@end quotation
@end example
@vindex this@r{, inside C@t{++} member functions}
-@cindex namespace in C++
+@cindex namespace in C@t{++}
@item
While a member function is active (in the selected stack frame), your
expressions have the same namespace available as the member function;
that is, @value{GDBN} allows implicit references to the class instance
-pointer @code{this} following the same rules as C++.
+pointer @code{this} following the same rules as C@t{++}.
@cindex call overloaded functions
@cindex overloaded functions, calling
-@cindex type conversions in C++
+@cindex type conversions in C@t{++}
@item
You can call overloaded functions; @value{GDBN} resolves the function
call to the right definition, with some restrictions. @value{GDBN} does not
Overload resolution is always performed, unless you have specified
@code{set overload-resolution off}. @xref{Debugging C plus plus,
-,@value{GDBN} features for C++}.
+,@value{GDBN} features for C@t{++}}.
You must specify @code{set overload-resolution off} in order to use an
explicit function signature to call an overloaded function, as in
@cindex reference declarations
@item
-@value{GDBN} understands variables declared as C++ references; you can use
-them in expressions just as you do in C++ source---they are automatically
+@value{GDBN} understands variables declared as C@t{++} references; you can use
+them in expressions just as you do in C@t{++} source---they are automatically
dereferenced.
In the parameter list shown when @value{GDBN} displays a frame, the values of
you have specified @samp{set print address off}.
@item
-@value{GDBN} supports the C++ name resolution operator @code{::}---your
+@value{GDBN} supports the C@t{++} name resolution operator @code{::}---your
expressions can use it just as expressions in your program do. Since
one scope may be defined in another, you can use @code{::} repeatedly if
necessary, for example in an expression like
@samp{@var{scope1}::@var{scope2}::@var{name}}. @value{GDBN} also allows
-resolving name scope by reference to source files, in both C and C++
+resolving name scope by reference to source files, in both C and C@t{++}
debugging (@pxref{Variables, ,Program variables}).
@end enumerate
-In addition, when used with HP's C++ compiler, @value{GDBN} supports
+In addition, when used with HP's C@t{++} compiler, @value{GDBN} supports
calling virtual functions correctly, printing out virtual bases of
objects, calling functions in a base subobject, casting objects, and
invoking user-defined operators.
@node C Defaults
-@subsubsection C and C++ defaults
+@subsubsection C and C@t{++} defaults
-@cindex C and C++ defaults
+@cindex C and C@t{++} defaults
If you allow @value{GDBN} to set type and range checking automatically, they
both default to @code{off} whenever the working language changes to
-C or C++. This happens regardless of whether you or @value{GDBN}
+C or C@t{++}. This happens regardless of whether you or @value{GDBN}
selects the working language.
If you allow @value{GDBN} to set the language automatically, it
recognizes source files whose names end with @file{.c}, @file{.C}, or
@file{.cc}, etc, and when @value{GDBN} enters code compiled from one of
-these files, it sets the working language to C or C++.
+these files, it sets the working language to C or C@t{++}.
@xref{Automatically, ,Having @value{GDBN} infer the source language},
for further details.
@c appear even if Mod-2 does not, but meanwhile ignore it. roland 16jul93.
@node C Checks
-@subsubsection C and C++ type and range checks
+@subsubsection C and C@t{++} type and range checks
-@cindex C and C++ checks
+@cindex C and C@t{++} checks
-By default, when @value{GDBN} parses C or C++ expressions, type checking
+By default, when @value{GDBN} parses C or C@t{++} expressions, type checking
is not used. However, if you turn type checking on, @value{GDBN}
considers two variables type equivalent if:
@end menu
@node Debugging C plus plus
-@subsubsection @value{GDBN} features for C++
+@subsubsection @value{GDBN} features for C@t{++}
-@cindex commands for C++
+@cindex commands for C@t{++}
-Some @value{GDBN} commands are particularly useful with C++, and some are
-designed specifically for use with C++. Here is a summary:
+Some @value{GDBN} commands are particularly useful with C@t{++}, and some are
+designed specifically for use with C@t{++}. Here is a summary:
@table @code
@cindex break in overloaded functions
@value{GDBN} breakpoint menus help you specify which function definition
you want. @xref{Breakpoint Menus,,Breakpoint menus}.
-@cindex overloading in C++
+@cindex overloading in C@t{++}
@item rbreak @var{regex}
Setting breakpoints using regular expressions is helpful for setting
breakpoints on overloaded functions that are not members of any special
classes.
@xref{Set Breaks, ,Setting breakpoints}.
-@cindex C++ exception handling
+@cindex C@t{++} exception handling
@item catch throw
@itemx catch catch
-Debug C++ exception handling using these commands. @xref{Set
+Debug C@t{++} exception handling using these commands. @xref{Set
Catchpoints, , Setting catchpoints}.
@cindex inheritance
@var{typename}.
@xref{Symbols, ,Examining the Symbol Table}.
-@cindex C++ symbol display
+@cindex C@t{++} symbol display
@item set print demangle
@itemx show print demangle
@itemx set print asm-demangle
@itemx show print asm-demangle
-Control whether C++ symbols display in their source form, both when
-displaying code as C++ source and when displaying disassemblies.
+Control whether C@t{++} symbols display in their source form, both when
+displaying code as C@t{++} source and when displaying disassemblies.
@xref{Print Settings, ,Print settings}.
@item set print object
Control the format for printing virtual function tables.
@xref{Print Settings, ,Print settings}.
(The @code{vtbl} commands do not work on programs compiled with the HP
-ANSI C++ compiler (@code{aCC}).)
+ANSI C@t{++} compiler (@code{aCC}).)
@kindex set overload-resolution
@cindex overloaded functions, overload resolution
@item set overload-resolution on
-Enable overload resolution for C++ expression evaluation. The default
+Enable overload resolution for C@t{++} expression evaluation. The default
is on. For overloaded functions, @value{GDBN} evaluates the arguments
and searches for a function whose signature matches the argument types,
-using the standard C++ conversion rules (see @ref{C plus plus expressions, ,C++
+using the standard C@t{++} conversion rules (see @ref{C plus plus expressions, ,C@t{++}
expressions}, for details). If it cannot find a match, it emits a
message.
@item set overload-resolution off
-Disable overload resolution for C++ expression evaluation. For
+Disable overload resolution for C@t{++} expression evaluation. For
overloaded functions that are not class member functions, @value{GDBN}
chooses the first function of the specified name that it finds in the
symbol table, whether or not its arguments are of the correct type. For
@item @r{Overloaded symbol names}
You can specify a particular definition of an overloaded symbol, using
-the same notation that is used to declare such symbols in C++: type
+the same notation that is used to declare such symbols in C@t{++}: type
@code{@var{symbol}(@var{types})} rather than just @var{symbol}. You can
also use the @value{GDBN} command-line word completion facilities to list the
available choices, or to finish the type list for you.
String constants consist of a sequence of characters enclosed by a
pair of like quotes, either single (@code{'}) or double (@code{"}).
Escape sequences in the style of C are also allowed. @xref{C
-Constants, ,C and C++ constants}, for a brief explanation of escape
+Constants, ,C and C@t{++} constants}, for a brief explanation of escape
sequences.
@item
Some @value{GDBN} commands have little use when debugging Modula-2 programs.
Five subcommands of @code{set print} and @code{show print} apply
-specifically to C and C++: @samp{vtbl}, @samp{demangle},
+specifically to C and C@t{++}: @samp{vtbl}, @samp{demangle},
@samp{asm-demangle}, @samp{object}, and @samp{union}. The first four
-apply to C++, and the last to the C @code{union} type, which has no direct
+apply to C@t{++}, and the last to the C @code{union} type, which has no direct
analogue in Modula-2.
The @code{@@} operator (@pxref{Expressions, ,Expressions}), while available
with any language, is not useful with Modula-2. Its
intent is to aid the debugging of @dfn{dynamic arrays}, which cannot be
-created in Modula-2 as they can in C or C++. However, because an
+created in Modula-2 as they can in C or C@t{++}. However, because an
address can be specified by an integral constant, the construct
@samp{@{@var{type}@}@var{adrexp}} is still useful.
@item
@emph{Set Literals} are defined by a name which was specified in a set
mode. The value delivered by a Set Literal is the set value. This is
-comparable to an enumeration in C/C++ language.
+comparable to an enumeration in C/C@t{++} language.
@item
@emph{Emptiness Literal} is predefined by @code{NULL}. The value of the
emptiness literal delivers either the empty reference value, the empty
@table @code
@kindex info address
+@cindex address of a symbol
@item info address @var{symbol}
Describe where the data for @var{symbol} is stored. For a register
variable, this says which register it is kept in. For a non-register
the exact address of the current instantiation of the variable.
@kindex info symbol
+@cindex symbol from address
@item info symbol @var{addr}
Print the name of a symbol which is stored at the address @var{addr}.
If no symbol is stored exactly at @var{addr}, @value{GDBN} prints the
@code{whatis}, it does not print a detailed description; second, it
lists all source files where a type is defined.
+@kindex info scope
+@cindex local variables
+@item info scope @var{addr}
+List all the variables local to a particular scope. This command
+accepts a location---a function name, a source line, or an address
+preceded by a @samp{*}, and prints all the variables local to the
+scope defined by that location. For example:
+
+@smallexample
+(@value{GDBP}) @b{info scope command_line_handler}
+Scope for command_line_handler:
+Symbol rl is an argument at stack/frame offset 8, length 4.
+Symbol linebuffer is in static storage at address 0x150a18, length 4.
+Symbol linelength is in static storage at address 0x150a1c, length 4.
+Symbol p is a local variable in register $esi, length 4.
+Symbol p1 is a local variable in register $ebx, length 4.
+Symbol nline is a local variable in register $edx, length 4.
+Symbol repeat is a local variable at frame offset -8, length 4.
+@end smallexample
+
@kindex info source
@item info source
Show the name of the current source file---that is, the source file for
@item info methods
@itemx info methods @var{regexp}
The @code{info methods} command permits the user to examine all defined
-methods within C++ program, or (with the @var{regexp} argument) a
-specific set of methods found in the various C++ classes. Many
-C++ classes provide a large number of methods. Thus, the output
+methods within C@t{++} program, or (with the @var{regexp} argument) a
+specific set of methods found in the various C@t{++} classes. Many
+C@t{++} classes provide a large number of methods. Thus, the output
from the @code{ptype} command can be overwhelming and hard to use. The
@code{info-methods} command filters the methods, printing only those
which match the regular-expression @var{regexp}.
@value{GDBN} could not find the full definition for a struct or class.
@item const/volatile indicator missing (ok if using g++ v1.x), got@dots{}
-The symbol information for a C++ member function is missing some
+The symbol information for a C@t{++} member function is missing some
information that recent versions of the compiler should have output for
it.
debugging info.
@kindex set debug overload
@item set debug overload
-Turns on or off display of @value{GDBN} C++ overload debugging
+Turns on or off display of @value{GDBN} C@t{++} overload debugging
info. This includes info such as ranking of functions, etc. The default
is off.
@kindex show debug overload
@item show debug overload
-Displays the current state of displaying @value{GDBN} C++ overload
+Displays the current state of displaying @value{GDBN} C@t{++} overload
debugging info.
@kindex set debug remote
@cindex packets, reporting on stdout
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