Red Hat ENTERPRISE LINUX 3 - SECURITY GUIDE, Manual

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72 Chapter 10. Examining Data
disable display
dnums
...
Disable the display of item numbers
dnums
. A disabled display item is not printed automatically,
but is not forgotten. It may be enabled again later.
enable display
dnums
...
Enable display of item numbers
dnums
. It becomes effective once again in auto display of its
expression, until you specify otherwise.
display
Display the current values of the expressions on the list, just as is done when your program stops.
info display
Print the list of expressions previously set up to display automatically, each one with its item
number, but without showing the values. This includes disabled expressions, which are marked
as such. It also includes expressions which would not be displayed right now because they refer
to automatic variables not currently available.
If a display expression refers to local variables, then it does not make sense outside the lexical context
for which it was set up. Such an expression is disabled when execution enters a context where one of
its variables is not defined. For example, if you give the command
display last_char
while inside
a function with an argument
last_char
, gdb displays this argument while your program continues to
stop inside that function. When it stops elsewhere--where there is no variable
last_char
--the display
is disabled automatically. The next time your program stops where
last_char
is meaningful, you
can enable the display expression once again.
10.7. Print settings
gdb provides the following ways to control how arrays, structures, and symbols are printed.
These settings are useful for debugging programs in any language:
set print address
set print address on
{No value for ‘ listitem>GDBN’} prints memory addresses showing the location of stack
traces, structure values, pointer values, breakpoints, and so forth, even when it also displays the
contents of those addresses. The default is
on
. For example, this is what a stack frame display
looks like with
set print address on
:
(gdb) f
#0
set_quotes (lq=0x34c78 " ", rq=0x34c88 " ")
at input.c:530
530 if (lquote != def_lquote)
set print address off
Do not print addresses when displaying their contents. For example, this is the same stack frame
displayed with
set print address off
:
(gdb) set print addr off
(gdb) f
#0
set_quotes (lq=" ", rq=" ") at input.c:530
530 if (lquote != def_lquote)