dbXtra and dbxtra

Info menu: debugging registers, memory locations, and expressions

The Info menu accesses commands that examine and modify registers and memory locations, and examine expressions.

Show

[dbxtra command: whatis arguments]
[dbxtra command: print arguments]
Shows the type and value of a program variable or expression. For input, use selected text or enter the text. For further discussion, see dbXtra(CP). The whatis command obtains the declaration of a specified name. The syntax is:

whatis [enum | union | struct | class] name

The name can be qualified with block names. By default, name is assumed to be the name of a variable in the program. Any of the optional keywords can specify that name be used as the name of an aggregate rather than a variable.

NOTE: The ``()'' characters can specify that name be used as the name of a function rather than a variable.

Where

Obtains a listing of the active functions and their arguments. The Up and Down Source menu buttons can change the current function to another one in the call stack.

Display

[dbxtra command: display arguments]
Adds a variable or expression specified by the <selected-text> or by the user to the Display window. Information is updated and displayed every time a stop point is reached. The Display window is created if it does not exist. All the scrolling capabilities available for other windows are also applicable to the Display window. If more expressions are specified than can be accommodated by the window, some of the expressions scroll off the screen. Their space is accessible by manipulating the scrolling region or by increasing the size of the Display window.

When used with the trace, stop, or when commands, the display command can constantly monitor the values of expressions. The syntax is:

display [expression [, expression ...]]

The values are updated whenever the prompt is printed. If no expression is specified, then a list of the current expressions being displayed is output to the Interaction window (dbxtra).

If expression evaluates to a (char *) data type -- that is, if a string expression is specified -- the maximum number of characters displayed will depend on the value of the $stringlen variable, the default value of which is 512.

Assign

[dbxtra command: assign assignment-statement]
Assigns a value of an expression to a named variable specified by the selected text or by the user. The syntax is:

assign variable = expression

Which

[dbxtra command: which identifier]
Displays the full qualification of an identifier selected or entered by the user. dbXtra returns the name of the identifier prepended with the names of the enclosing scopes that the identifier is associated with.

Print

[dbxtra command: print arguments]
Displays the value of an expression. The syntax is:

print expression [, expression ...]

If expression evaluates to a (char *) data type -- that is, if a string expression is specified -- the maximum number of characters displayed depends on the value of the $stringlen variable.

Xref

[dbxtra command: xref identifier]
The xref command displays cross-reference information for a specified identifier, a variable, function, or macro. The cross-reference information is displayed in up to three sections. A section containing a list of functions and file or line number pairs, where the identifier is referenced, is always displayed. The other two sections are displayed only if the specified identifier is a function or macro. The second section contains a list of functions or macros that are called by the specified identifier. The third section contains a list of global variables, as well as parameterless macros, which are referenced by the named function. In both of these sections, an ``M'' as the first character of a line indicates that the identifier listed on the line is a macro.

For example, the following is the sample output when a global variable is used:

   (dbxtra) xref suit_strings
   Referenced from:
      format_hand  "deal.c": 102 107
      log_deal     "dealer.c": 329

Whereas, the following is the sample output when a function name is used:

   (dbxtra) xref deal_hands
   Referenced from:
      main      "dealer.c": 49
   References functions/macros: "deal.c"
      Deal      45
      qsort      46
   References variables/macros: "deal.c"
      card_compare   46

The bindable dbXtra editing command show_xref, as described in ``dbxtra screen functions'', can list the sources surrounding each of the line numbers produced by the xref command.

Variables

[dbxtra command: dump arguments]
Displays the names and values of variables local to the current function. The syntax is:

dump [function] [> filename]

If function is not specified, then the current one is used. If the function is given as ".", then all active variables are dumped.

Registers

[dbxtra command: regs]
[dbxtra command: fpregs]
Displays the contents of the general and floating point hardware registers of the processor.

Memory

Displays the contents of program memory.