dxdb(1X) dxdb(1X)
Name
dxdb - DECwindows debugger
Syntax
dxdb [options] file [coredump]
Description
The dxdb debugger is a DECwindows utility that lets you debug a C program, view its source code, and fix bugs found in the code. It uses
many of the same methods as the dbx(1) debugger.
Options
-bd color Specifies the color of the window's border (color displays only). The default is specified by means of the Session
Manager's Customize Window dialog box.
-bg color Specifies the color of the window's background (color displays only). The default is specified by means of the Session
Manager's Customize Window dialog box.
-d dispname Specifies the display screen on which dxdb displays its window. If the display option is not specified, dxdb uses the
display screen specified by your DISPLAY environment variable. The display option has the format hostname:number.
Using two colons (::) instead of one (:) indicates that DECnet is to be used for transport. The default is :0. For
more information, see
-display dispname This option is the same as the -d option.
-fg color Specifies the color of the text (color displays only). The default is black.
-fn font Specifies the font for all windows except the index list box. The default font is menu12.
-geometry Specifies the width, length, and location of the dxdb window. If the geometry option is not specified, dxdb uses
default values. The geometry option has the format [widthxlength][{+-}x{+-}y]. For more information about the screen
coordinate system, see
file A C object file compiled with the -g option of the cc(1) command. The -g option produces the appropriate symbol infor-
mation in the object file.
coredump A core file that you can access through dxdb to examine the state of a program that crashed.
-I dir Adds dir to the list of directories that dxdb searches when looking for source files. Normally, dxdb searches only in
the current directory.
-t Specifies the title to be listed in the main window's title bar.
Menus
When you invoke the debugger, dxdb displays the Control window. The menu bar of the Control window contains the following menus:
o File
o Control
o Options
o Windows
o Functions
o Help
File Menu
The File menu lets you perform global actions affecting the entire debugging session. It contains the following items:
Open... Reads in a new source file.
Make/Restart Builds a new executable and restarts the debugger.
Edit Edits a source file.
Quit Terminates the dxdb session.
Control Menu
The Control menu controls program execution. It contains the following items:
Run Runs the program.
Step Runs the program in single- or multiple-line increments. You set the step count using the Step window (see Options Menu).
Skip Runs the program in single- or multiple-line increments but views all code of a subroutine as a single step. You set the
skip count using the Skip window (see Options Menu).
Continue Restarts a program after a Stop command, a breakpoint, or a Skip or Step function.
Stop Stops execution of the program.
Return Continues execution until the current procedure returns.
Options Menu
The Options menu items create the following windows:
Run... Lets you supply arguments to a program. The Run window consists of an input area and the following control buttons:
o Run with Argument
o Run
o Close
To supply an argument to a program, enter it in the input area and click on the Run with Arguments button. To run a program
without specifying an argument, click on the Run button. Clicking on the Close button quits the window.
Step... Specifies the line increment (step count) in which dxdb runs a program. The Step window consists of an input area, plus (+)
and minus (-) accelerator buttons, and the following command buttons:
o Step Count
o Step Once
o Close
To set a step count, either click on the appropriate accelerator button until you reach the desired count or enter the count
in the input area. Click on the Step Count button, and then return to the Control window and click on the Step button. The
debugger executes the specified number of lines of code each time you click on the Step button.
To return to single-step increments, use the Step Once button.
Skip... Sets the number of lines (skip count) that dxdb skips when running a program. The Skip window consists of an input area,
plus (+) and minus (-) accelerator buttons, and the following command buttons:
o Skip Count
o Skip Once
o Close
You set the skip count as you set the step count. However, if dxdb encounters a subroutine call when executing a skip, it
executes the entire routine as a single skip and resumes the skip count when it returns from the call.
Windows Menu
The Windows menu items create the following windows:
Assign... Assigns a value to a specified variable. The Assign window consists of the following input areas:
o Variable prompt
o Value prompt
o Assign button
o Close button
To assign a value to a variable, enter a variable in the Variable text field, enter a value in the Value text field, and
click on the Assign button.
Breakpoints... Displays the current breakpoints and tracepoints. To delete a breakpoint or tracepoint, select it in the text and click on
the Delete button.
Dump... Displays the values of all currently active local variables. The debugger updates the contents of this window each time you
stop execution of the program (using the Step, Skip, or Stop function, or by setting a breakpoint).
Examine... Displays the values of specified variables. This window consists of the following areas:
o Text area
o Examine prompt
o Add button
o Delete button
o Close button
To examine a variable, enter its name in the Examine text field and click on the Add button. The debugger displays the vari-
able's current value in the window's text area.
To delete a variable from the Examine window, click on its name in the window's text area and then click on the Delete but-
ton.
Stack Lets you view elements of the program execution stack. The program that dxdb is running places an entry on this stack each
time program control executes one of its routines. Each element on the stack contains the routine name and the parameters
passed to that routine. The debugger updates this window each time you stop the execution of the program.
Make... Displays the output of the Make/Restart command. The Restart Command field is executed when the Make/Restart command is
executed and can be edited to suit the program being debugged.
Functions Menu
The Functions menu contains the following items:
Whatis Returns the data type of a variable. Select a variable currently displayed in the Source window and then choose Whatis from
the Functions menu. Whatis returns the variable's data type in the following format:
variable - routine.datatype variable;
Whereis Returns a list of routines from which you can locate a variable. Select a variable from the Source window and then choose
Whereis from the Functions menu. Whereis returns the variable's location in the following format:
routine.variable routine.variable ...
Which Returns the scope of the variable (local or global) that is currently active. Select a variable from the Source window and
then choose Which from the Functions menu. Which returns the variable's scope in the following format:
variable - rotuine.function...variable
Help Menu
The Help menu displays information about dxdb.
In addition to those pulldown menus, there are several pop-up menus:
Control Pop-up Menu
The Control pop-up menu duplicates the Control pull-down menu; it controls program execution. To invoke this menu, press MB2 on the Source
Area.
Examine Pop-up Menu
The Examine pop-up menu lets you examine the value of variables, and set and delete breakpoints and tracepoints. To invoke this menu,
press the Shift key and click MB2 in the Source Area. The menu items operate on text in the Source area. If you position the pointer over
some text before invoking the menu, the menu options refer to that text. If there is no text under the pointer, dxdb uses text that is
highlighted. The menu items are as follows:
Print Prints the value of a variable in the text area.
Print * Prints the value of a variable treated as a pointer.
Examine Enters a variable in the Examine window.
Examine * Enters a variable in the Examine window treated as a pointer.
Delete Examine Removes a variable from the Examine window.
Stop in Func Sets a breakpoint in the selected function.
Trace in Func Sets a tracepoint in the selected function.
The Examine and Print options have submenus that let you view the values in hexadecimal notation.
Breakpoints Pop-up Menu
This menu lets you set and delete breakpoints. To invoke the menu, press MB2 in the Margin Area. All options operate on the text indicated
by the pointer when you invoke the menu. The menu options are as follows:
Set at Line Sets a breakpoint at the specified line.
Set in Func Sets a breakpoint in the specified function.
Global Sets a global breakpoint.
Random Func Sets a breakpoint in any function in the program.
Random Line Sets a breakpoint at any line in the program.
Delete BP Deletes a breakpoint whose symbol is under the cursor.
The Set at Line and Set in Func options have submenus that let you set conditional breakpoints.
Tracepoints Pop-up Menu
This menu lets you set and delete tracepoints. To invoke the menu, press Shift/MB2 on the Margin Area. All options operate on the text
indicated by the pointer when you invoke the menu. The Tracepoint pop-up menu has the following items:
Trace Global Sets a global tracepoint.
Trace at Line Sets a tracepoint at the specified line.
Trace in Func Sets a tracepoint in the specified function.
Delete Trace Deletes a tracepoint whose symbol is under the cursor.
X Defaults
The dxdb debugger uses the values in the .Xdefaults file when you logged in and uses the appropriate resource specification to customize
the appearance or characteristics of its windows. The format for a resource specification in the .Xdefaults file is as follows:
[name*]resource: value
name Specifies the application name or, in the case of toolkit-based applications, the name string that restricts the resource
assignment to that application or to a component of an application. If this argument is not specified, the resource assign-
ment is globally available to all X applications.
resource Specifies the X resource.
value Specifies the value that is to be assigned to the resource.
Because each X-based application can consist of a combination of widgets (for example, push buttons and a scroll bar), you can form the
name string by adding widget class and name identifiers to the string. For additional information about adding class and name identifiers,
see
Files
/usr/lib/X11/app-defaults/Db
~/.Xdefaults
core
See Also
dbx(1), dxterm(1X), X(1X)
Guide to the dxdb Debugger
dxdb(1X)