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xxgdb - X window system interface to the gdb debugger.


xxgdb [ -toolkitoption ... ] [-xxgdboption ... ] [-gdboption ... ] [objfile [ corefile ]]


Xxgdb is a graphical user interface to the gdb debugger under the X Window System. It
provides visual feedback and mouse input for the user to control program execution through
breakpoints, to examine and traverse the function call stack, to display values of
variables and data structures, and to browse source files and functions.

Xxgdb allows initial gdb commands stored in the file .gdbinit to be executed immediately
after the symbolic information is read. If .gdbinit does not exist in the current
directory, the user's home directory is searched ( /.gdbinit). Option -nx can be used to
prevent xxgdb from executing this file. Option -i can be used to change the file name of
command file.

Objfile is an object file produced by a compiler with the appropriate option (-g)
specified to produce symbol table information for gdb.

If a file named core exists in the current directory or a corefile is specified, xxgdb can
be used to examine the state of the program when the core dump occurred.

The name of the debugger invoked by xxgdb is, by default, gdb, but it can be overridden
with the environment variable XXGDB_DEBUGGER or with the db_name option.


Xxgdb accepts all of the standard X Toolkit command line options (see X(1)), and all the
gdb options (see gdb(1)), plus the following xxgdb specific options:

-db_name debuggername
Specify the name of the debugger to override the default "gdb". WARNING : by
default prompt is the name of the debugger enclosed in parenthesis followed by a
space. So if the prompt is still "(gdb) ", you HAVE TO use -db_prompt "gdb"

-db_prompt promptstring
Specify to xxgdb what is the debugger prompt. The default is to expect the prompt
to be the name of the debugger enclosed in parenthesis followed by a space (eg,
"(gdb) ").

-i filename
Specify the filename of initial gdb command file. The default is ".gdbinit".

-nx Do not execute .gdbinit file (or file specified with -i)

Uses a 64x64 icon instead of the default 48x48 icon.


Xxgdb consists of the following subwindows:

File Window Display the full pathname of the file displayed in the source window,
and the line number of the caret.

Source Window Display the contents of a source file.

Message Window Display the execution status and error messages of xxgdb .

Command Window Provide a list of the common gdb commands which are invoked by simply
clicking the LEFT mouse button.

Dialogue Window Provide a typing interface to gdb.

Display Window Provide a window for displaying variables each time execution stops.

Popup Windows Provide windows for displaying variables (see "Displaying C Data
Structures" below).

The relative sizes of the source window, command window, and the dialogue window can be
adjusted by dragging the grip (a small square near the right edge of a horizontal border)
with the LEFT mouse button down.


Text selection in the source window is modified to make it easier to select C expressions.
LEFT mouse button down selects a C expression by highlighting it in reverse-video. LEFT
mouse button down also positions the caret and updates the line label accordingly.

C expression selection is based on the resource delimiters which determines the set of
characters that delimits a C expression. (The default word selection behavior in the
Athena text widget selects a word delimited by white spaces.) Text selection adjustment
is possible by holding the LEFT mouse button down and dragging.

A LEFT mouse button click with the SHIFT button down prints the value of the expression


Pressing the LEFT mouse button scrolls the text forward, whereas pressing the RIGHT mouse
button scrolls the text backward. The amount of scrolling depends on the distance of the
pointer button away from the top of the scrollbar. If the button is pressed at the top of
the scrollbar, only one line of text is scrolled. If the button is pressed at the bottom
of the scrollbar, one screenful of text is scrolled.

Pressing the MIDDLE mouse button changes the thumb position of the scrollbar. Dragging
the MIDDLE mouse button down moves the thumb along and changes the text displayed.


If compiled, with the right option, xxgdb can use a separate io window to talk to gdb, so
program output is not confused with gdb output. Type command 'iowin' in Dialogue Window
to create io window. If you get 'Undefined command' error message, then xxgdb was not
compiled for that feature. The program xxgdbiowin is used for this io window.

If xxgdb was compiled with iowin support, typing 'noiowin' will close the io window and
reset the controlling terminal of the debugger.


Execution Commands
run Begin program execution.

cont Continue execution from where it stopped.

next Execute one source line, without stepping into any function call.

step Execute one source line, stepping into a function if the source line contains
a function call.

finish Continue execution until the selected procedure returns; the current procedure
is used if none is selected.

Breakpoint Commands
break Stop program execution at the line or in the function selected. To set a
breakpoint in the program, place the caret at the start of the source line or on
the function name and click the break button. A stop sign will appear next to
the source line.

tbreak Set a breakpoint enabled only for one stop. This is the same as the break
button except the breakpoint is automatically disabled the first time it hit.

delete Remove the breakpoint on the source line selected or the breakpoint number

show brkpts
Show the current breakpoints (both active and inactive).

Stack Commands
stack Show a stack trace of the functions called.

up Move up one level on the call stack.

down Move down one level on the call stack.

Data Display Commands
print Print the value of a selected expression. (also see "Displaying C Data
Structures" below)

print * Print the value of the object the selected expression is pointing to. (also see
"Displaying C Data Structures" below)

display Display the value of a selected expression in the display window, updating its
value every time execution stops.

undisplay Stop displaying the value of the selected expression in the display window. If
the selected expression is a constant, it refers to the display number
associated with an expression in the display window.

args Print the arguments of the selected frame.

show display
Show the names of currently displayed expressions.

locals Print the local variables of the selected frame.

stack Print a backtrace of the entire stack.

Miscellaneous Commands
search Pop up a search panel which allows both forward (>>) and reverse (<<) search of
text strings in the source file. Hitting carriage return after entering the search
string will begin a forward search and pop down the search panel.

file Pop up a directory browser that allows the user to move up and down in the
directory tree, to select a text file to be displayed, to select an executable file
to debug, or to select a core file to debug. Directory entries are marked with a
trailing slash (`/') and executables with a trailing asterisk (`*'). Filenames
beginning with a dot (`.') or ending with a tilde (`~') are not listed in the

search Pop up a search panel which allows both forward (>>) and reverse (<<) search of
text strings in the source file. Hitting carriage return after entering the search
string will begin a forward search and pop down the search panel.

yes Send 'y' (yes) to gdb. To be used when gdb requires a yes/no response.

no Send 'n' (no) to gdb. To be used when gdb requires a yes/no response.

quit Exit xxgdb.

I/O Win
Create io window.

No I/O Win
Delete io window.

Displaying C Data Structures
Xxgdb provides some primitive support for graphically displaying C structures and the
ability of following pointers. Pressing the RIGHT mouse button on the print (or print *)
command button displays the value of the selected expression (or the value the selected
expression is pointing to) in a popup. If the value is a pointer or a structure
containing pointers, the user can examine the value of the object that pointer is pointing
to by clicking the pointer value. This will create another popup that displays the object
the pointer points to. Clicking the label of the popup pops down itself and all of its


To change the default values of widget resources used in xxgdb, you need to reference the
widgets by name or by class. The widget hierarchies for the main window, the file menu,
the search dialog box, and the popup data display used in xxgdb are shown as follows, with
the name of the widget followed by the name of its class in parentheses:

Main window:
toplevel (ToplevelShell)
vpane (Paned)
fileWindow (Form)
fileLabel (Label)
lineLabel (Label)
sourceForm (Form)
sourceWindow (AsciiText)
messageWindow (Label)
commandWindow (Box)
run (Command)
cont (Command)
next (Command)
step (Command)
finish (Command)
break (Command)
tbreak (Command)
delete (Command)
up (Command)
down (Command)
print (Command)
print * (Command)
display (Command)
undisplay (Command)
args (Command)
locals (Command)
stack (Command)
search (Command)
file (Command)
show display (Command)
show brkpts (Command)
yes (Command)
no (Command)
quit (Command)
dialogWindow (AsciiText)
displayWindow (AsciiText)

File menu:
File Directory (TransientShell)
popup (Paned)
fileMenuLabel (Label)
fileMenu (List)
cancelButton (Command)

Search dialog box:
Search (TransientShell)
searchPopup (Dialog)
<< (Command)
>> (Command)
DONE (Command)

Data display popup:
Data Popup (TransientShell)
popup (Form)
label (Label)
dataDpyWindow (AsciiText)

In addition to the standard X resources, xxgdb uses the following application-specific
resources for user customization. The value in parentheses is the default value.

bell If True, the bell is on. (True)

If True, the display window appears on start up. (False)

The set of delimiters for word selection. (" !%^&*()+=~|;:{},/#<?\"\n\t")

Color of the stop sign. (Red)

Color of the arrow sign. (Blue)

Color of the updown sign. (Blue)

Color of the bomb sign. (Red)

Maximum height of the data display window. (300)

Maximum width of the data display window. (600)

prompt The prompt string used in xxgdb. ("(xxgdb) ")

The name of the debugger program. ("gdb")

The prompt string of the debugger program. ("(gdb) ")

The filename of initial command file. (".gdbinit")

nx If True, xxgdb will not execute .gdbinit at start-up. (False)

When displaying source code, the width (in spaces) of a tab. (8)

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