xxgdb(1) 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".
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 selected.


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

Begin program execution.
Continue execution from where it stopped.
Execute one source line, without stepping into any function call.
Execute one source line, stepping into a function if the source line contains a function call.
Continue execution until the selected procedure returns; the current procedure is used if none is selected.

Breakpoint Commands

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.
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.
Remove the breakpoint on the source line selected or the breakpoint number selected.
show brkpts
Show the current breakpoints (both active and inactive).

Stack Commands

Show a stack trace of the functions called.
Move up one level on the call stack.
Move down one level on the call stack.

Data Display Commands

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 the value of a selected expression in the display window, updating its value every time execution stops.
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.
Print the arguments of the selected frame.
show display
Show the names of currently displayed expressions.
Print the local variables of the selected frame.
Print a backtrace of the entire stack.

Miscellaneous Commands

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


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.
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)
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")
If True, xxgdb will not execute .gdbinit at start-up. (False)
When displaying source code, the width (in spaces) of a tab. (8)


a.out           default object file
core            default core file
~/XDbx          resources file (or /usr/lib/X11/app-defaults/XDbx)
.gdbinit                local initial commands file
~/.gdbinit      user's initial commands file


Copyright 1989 The University of Texas at Austin.
Copyright 1990 Microelectronics and Computer Technology Corporation.
Copyright 1990-1994 Thomson Consumer Electronics, Inc.


Po Cheung.
Pierre Willard.