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GDB^ QUICK
REFERENCE
GDB^ Version^
4
Essential^ Commands gdb^ program^ [cor
e]^ debug^ progr
am^ [using^ coredump
core]
b^ [^ le:]function
set^ breakp
oint^ at^ function
[in^ le]
run^ [arglist]^
start^ your^ program
[with^ arglist]
bt^
backtrace:^ displa
y^ program^ stack p^ expr^
display^ the^ value
of^ an^ expression c^
continue^ running
your^ program n^
next^ line,^ stepping
over^ function^ calls s^
next^ line,^ stepping
into^ function^ calls
Starting^ GDB gdb^
start^ GDB,^ with
no^ debugging^
les
gdb^ program^
b^ egin^ debugging
program gdb^ program^ cor
e^ debug^ coredump
core^ pro^ duced^
by program gdb^ --help^
describ^ e^ command
line^ options
Stopping^ GDB quit^
exit^ GDB;^ also^
q^ or^ EOF^ (eg^ C-d
INTERRUPT^
(eg^ C-c)^ terminate
current^ command,
or send^ to^ running
pro^ cess
Getting^ Help help^
list^ classes^ of^ commands help^ class^
one-line^ descriptions
for^ commands^
in class help^ command^
describ^ e^ command
Executing^ y
our^ Program
run^ arglist^
start^ your^ program
with^ arglist run^
start^ your^ program
with^ current^ argumen
t list run^ :^ :^ :^ <inf^ >outf
start^ your^ program
with^ input,^ output redirected kill^
kill^ running^ program tty^ dev^
use^ dev^ as^ stdin
and^ stdout^ for^
next^ run
set^ args^ arglist
sp^ ecify^ arglist
for^ next^ run set^ args^
sp^ ecify^ empty^ argumen
t^ list show^ args^
display^ argumen
t^ list show^ environment
show^ all^ environmen
t^ variables show^ env^ var^
show^ value^ of^ en
vironment^ variable
var
set^ env^ var^ string
set^ environmen
t^ variable^ var unset^ env^ var^
remove^ var^ from
environment
Shell^ Commands cd^ dir^
change^ working^
directory^ to^ dir pwd^
Print^ working^ directory make^ :^ :^ :^
call^ \make" shell^ cmd^
execute^ arbitrary
shell^ command^
string
[^ ]^ surround^ optional
arguments^
:^ :^ :^ show^ one^ or^
more^ arguments
c^ 1991,^1992 Free
Software^ Foundation,
Inc.^ Permissions
Breakp on back
oints^ and^ W
atchp^ oints
break^ [^ le:]line b^ [^ le:]line
set^ breakp^ oint^ at
line^ numb^ er^ [in
le]
eg:^ break^ main.c:
break^ [^ le:]function
set^ breakp^ oint^
at^ function^ [in^
le]
break^ +o^ set break^ - o^ set
set^ break^ at^ o^
set^ lines^ from^ curren
t^ stop
break^ *addr^
set^ breakp^ oint^ at
address^ addr break^
set^ breakp^ oint^ at
next^ instruction break^ :^ :^ :^ if^ expr
break^ conditionally
on^ nonzero^ expr
cond^ n^ [expr]^
new^ conditional
expression^ on^ breakp
oint n;^ make^ unconditional
if^ no^ expr tbreak^ :^ :^ :^
temp^ orary^ break;
disable^ when^ reac
hed
rbreak^ regex^
break^ on^ all^ functions
matching^ regex watch^ expr^
set^ a^ watchp^ oin
t^ for^ expression^
expr
catch^ x^
break^ at^ C++^ handler
for^ exception^ x info^ break^
show^ de^ ned^ breakp
oints info^ watch^
show^ de^ ned^ watc
hp^ oints clear^
delete^ breakp^ oin
ts^ at^ next^ instruction
clear^ [^ le:]fun
delete^ breakp
oints^ at^ entry^ to
fun()
clear^ [^ le:]line
delete^ breakp
oints^ on^ source^
line
delete^ [n]^
delete^ breakp^ oin
ts^ [or^ breakp^ oin
t^ n]
disable^ [n]^
disable^ breakp^ oin
ts^ [or^ breakp^ oin
t^ n]
enable^ [n]^
enable^ breakp^ oin
ts^ [or^ breakp^ oin
t^ n]
enable^ once^ [n
]^ enable^ breakp
oints^ [or^ breakp
oint^ n];
disable^ again^ when
reached
enable^ del^ [n]^
enable^ breakp^ oin
ts^ [or^ breakp^ oin
t^ n];
delete^ when^ reac
hed ignore^ n^ count
ignore^ breakp
oint^ n,^ count^ times
commands^ n^ [silent]^ command-list
execute^ GDB^ command-list
every^ time breakp^ oint^ n^ is^
reached.^ [silent
suppresses^ default
display]
end^
end^ of^ command-list
Program^ Stac
k
backtrace^ [n] bt^ [n]
print^ trace^ of^ all
frames^ in^ stack;
or^ of^ n frames|innermost
if^ n>0,^ outermost
if n<
frame^ [n]^
select^ frame^ num
b^ er^ n^ or^ frame^
at address^ n;^ if^ no
n,^ display^ curren
t^ frame
up^ n^
select^ frame^ n^ frames
up down^ n^
select^ frame^ n^ frames
down
info^ frame^ [addr
]^ describ^ e^ selected
frame,^ or^ frame
at^ addr
info^ args^
arguments^ of^ selected
frame info^ locals^
lo^ cal^ variables^ of
selected^ frame
info^ reg^ [rn]:^ :
:
info^ all-reg^ [
register^ v rn]
alues^ [for^ regs^ rn
]^ in^ selected
frame;^ all-reg
includes^ oating
p^ oint
info^ catch^
exception^ handlers
active^ in^ selected frame
Execution^ Con
trol
continue^ [count
]
c^ [count]
continue^ running;
if^ count^ sp^ eci^
ed, ignore^ this^ breakp
oint^ next^ count^
times
step^ [count] s^ [count]
execute^ until^ another
line^ reached;^ rep
eat count^ times^ if^ sp
eci^ ed
stepi^ [count] si^ [count]
step^ by^ machine
instructions^ rather
than source^ lines
next^ [count] n^ [count]
execute^ next^ line,
including^ any^ function calls
nexti^ [count] ni^ [count]
next^ machine^ instruction
rather^ than source^ line
until^ [location
]^ run^ until^
next^ instruction
(or^ location)
finish^
run^ until^ selected
stack^ frame^ returns
return^ [expr]^
p^ op^ selected^ stac
k^ frame^ withoutexecuting [setting^ return^ value]
signal^ num^
resume^ execution
with^ signal^ s^ (none
if^0 )
jump^ line jump^ *address
resume^ execution
at^ sp^ eci^ ed^ line
numb^ er or^ address set^ var=expr^
evaluate^ expr^ without
displaying^ it;^ use for^ altering^ program
variables
Display print^ [/f^ ]^ [expr
]
p^ [/f^ ]^ [expr]
show^ value^ of^ expr
[or^ last^ value^ $
]
according^ to^ format
f: x^
hexadecimal d^
signed^ decimal u^
unsigned^ decimal o^
o^ ctal t^
binary a^
address,^ absolute
and^ relative c^
character f^
oating^ p^ oint
call^ [/f^ ]^ expr^
like^ print^ but^ do
es^ not^ display^ void
x^ [/Nuf^ ]^ expr^
examine^ memory
at^ address^ expr
optional^ format^
sp^ ec^ follows^ slash N^
count^ of^ how^ man
y^ units^ to^ displa
y
u^
unit^ size;^ one^ of^ b^ individual
bytes h halfwords (two^ bytes) w words (four^ bytes) g giant words^ (eight^ bytes) f^
printing^ format.
Any^ print^ format,
or s^ null-terminated
string i^ machine^ instructions
disassem^ [addr
]^ display^ memory
as^ machine^ instructions
Automatic^
Display
display^ [/f^ ]^ expr
show^ value^ of
expr^ each^ time^
program
stops^ [according
to^ format^ f^ ]
display^
display^ all^ enabled
expressions^ on^
list
undisplay^ n^
remove^ numb^ er(s)
n^ from^ list^ of automatically^ displa
yed^ expressions disable^ disp^ n
disable^ displa
y^ for^ expression(s)
numb^ er^ n
enable^ disp^ n^
enable^ display^ for
expression(s)^ n
umb^ er^ n
info^ display^
numb^ ered^ list^ of
display^ expressions
Expressions expr^
an^ expression^ in
C,^ C++,^ or^ Mo
dula- (including^ function
calls),^ or: addr^ @len^
an^ array^ of^ len^
elements^ b^ eginning
at addr le::nm^
a^ variable^ or^ function
nm^ de^ ned^ in^
le
ftypegaddr^
read^ memory^ at
addr^ as^ sp^ eci^ ed
type
$^
most^ recent^ displa
yed^ value $n^
nth^ displayed^ value $$^
displayed^ value^
previous^ to^ $ $$n^
nth^ displayed^ value
back^ from^ $ $^
last^ address^ examined
with^ x $^
value^ at^ address
$var^
convenience^ variable;
assign^ any^ value show^ values^ [n
]^ show^ last
10 values^ [or^ surrounding
$n]
show^ convenience
display^ all^ con
venience^ variables
Symb^ ol^ Table info^ address^ s
show^ where
symb^ ol^ s^ is^ stored info^ func^ [regex
]^ show^ names,
typ^ es^ of^ de^ ned
functions (all,^ or^ matching
regex) info^ var^ [regex
]^ show^ names,
typ^ es^ of^ global
variables^ (all, or^ matching^ regex
whatis^ [expr] ptype^ [expr]
show^ data^ typ^ e^
of^ expr^ [or^ $]^ withoutevaluating; ptype^ gives^ more^ detail ptype^ type^
describ^ e^ typ^ e,^ struct,
union,^ or^ enum
GDB^ Scripts source^ script^
read,^ execute^ GDB
commands^ from
le script define^ cmdcommand-list
create^ new^ GDB
command^ cmd;
execute script^ de^ ned^ by
command-list end^
end^ of^ command-list document^ cmdhelp-text
create^ online^ do
cumentation^ for
new^ GDB command^ cmd end^
end^ of^ help-text
Signals handle^ signal^ act
sp^ ecify^ GDB
actions^ for^ signal
print^
announce^ signal noprint^
b^ e^ silent^ for^ signal stop^
halt^ execution^ on
signal nostop^
do^ not^ halt^ execution pass^
allow^ your^ program
to^ handle^ signal nopass^
do^ not^ allow^ your
program^ to^ see
signal
info^ signals^
show^ table^ of^ signals,
GDB^ action^ for each
Debugging^
Targets
target^ type^ par
am^ connect^ to
target^ machine,
pro^ cess,^ or^ le
help^ target^
display^ available
targets attach^ param^
connect^ to^ another
pro^ cess detach^
release^ target^ from
GDB^ control
Controlling
GDB
set^ param^ value
set^ one^ of^
GDB's^ internal^
parameters
show^ param^
display^ current^
setting^ of^ parameter Parameters^ understo
o^ d^ by^ set^ and^
show: complaints^ limit
numb^ er^ of^ messages
on^ unusual^ sym
b^ ols
confirm^ on/o^
enable^ or^ disable
cautionary^ queries editing^ on/o^
control^ readline
command-line^ editing height^ lpp^
numb^ er^ of^ lines^
b^ efore^ pause^ in^
display
language^ lang^
Language^ for^ GDB
expressions^ (auto
,^ c or^ modula-2) listsize^ n^
numb^ er^ of^ lines^
shown^ by^ list prompt^ str^
use^ str^ as^ GDB
prompt radix^ base^
o^ ctal,^ decimal,^ or
hex^ numb^ er representation verbose^ on/o^
control^ messages
when^ loading^ sym
b^ ols
width^ cpl^
numb^ er^ of^ characters
b^ efore^ line^ folded write^ on/o^
Allow^ or^ forbid^
patching^ binary,
core^ les (when^ reop^ ened
with^ exec^ or^ core
history^ :^ :^ : h^ :^ :^ :
groups^ with^ the
following^ options: h^ exp^ o^ /on^
disable/enable^ readline
history expansion h^ file^ lename
le^ for^ recording
GDB^ command
history
h^ size^ size^
numb^ er^ of^ commands
kept^ in^ history
list
h^ save^ o^ /on^
control^ use^ of^ external
le^ for^ command history print^ :^ :^ : p^ :^ :^ :
groups^ with^ the
following^ options: p^ address^ on/o
print^ memory
addresses^ in^ stac
ks,^ values
p^ array^ o^ /on^
compact^ or^ attractiv
e^ format^ for^ arra
ys
p^ demangl^ on/o
source^ (demangled)
or^ internal^ form
for C++^ symb^ ols p^ asm-dem^ on/o
demangle^ C++
symb^ ols^ in^ mac
hine- instruction^ output p^ elements^ limit
numb^ er^ of^ arra
y^ elements^ to^ displa
y
p^ object^ on/o^
print^ C++^ deriv
ed^ typ^ es^ for^ ob^ jects p^ pretty^ o^ /on
struct^ displa
y:^ compact^ or^ inden
ted
p^ union^ on/o^
display^ of^ union
memb^ ers p^ vtbl^ o^ /on^
display^ of^ C++
virtual^ function
tables
show^ commands^
show^ last^10 commands show^ commands^
n^ show^10 commands
around^ numb^ er
n
show^ commands^
+^ show^ next
10 commands Working^ Files file^ [^ le]^
use^ le^ for^ b^ oth
symb^ ols^ and^ executable;with no arg, discard^ b^ oth core^ [^ le]^
read^ le^ as^ coredump;
or^ discard exec^ [^ le]^
use^ le^ as^ executable
only;^ or^ discard symbol^ [^ le]^
use^ symb^ ol^ table
from^ le;^ or^ discard load^ le^
dynamically^ link
le^ and^ add^ its
symb^ ols
add-sym^ le^ addr
read^ additional
symb^ ols^ from^
le, dynamically^ loaded
at^ addr info^ files^
display^ working
les^ and^ targets
in^ use
path^ dirs^
add^ dirs^ to^ fron
t^ of^ path^ searched
for executable^ and^
symb^ ol^ les show^ path^
display^ executable
and^ symb^ ol^ le
path
info^ share^
list^ names^ of^ shared
libraries^ curren
tly loaded
Source^ Files dir^ names^
add^ directory^ names
to^ front^ of^ source path dir^
clear^ source^ path show^ dir^
show^ current^ source
path list^
show^ next^ ten^ lines
of^ source list^ -^
show^ previous^ ten
lines list^ lines^
display^ source^ surrounding
lines,^ sp^ eci^ ed as: [^ le:]num^
line^ numb^ er^ [in^
named^ le] [^ le:]function^
b^ eginning^ of^ function
[in^ named^ le] +o^
o^ lines^ after^ last
printed
o^ lines^ previous
to^ last^ printed *address^
line^ containing^ addr
ess list^ f,l^
from^ line^ f^ to^ line
l info^ line^ num
show^ starting,
ending^ addresses
of compiled^ co^ de^ for
source^ line^ num info^ source^
show^ name^ of^ curren
t^ source^ le info^ sources^
list^ all^ source^ les
in^ use forw^ regex^
search^ following^
source^ lines^ for^
regex
rev^ regex^
search^ preceding
source^ lines^ for
regex
GDB^ under
GNU^ Emacs
M-x^ gdb^
run^ GDB^ under^
Emacs C-h^ m^
describ^ e^ GDB^ mo
de M-s^
step^ one^ line^ (step
M-n^
next^ line^ (next) M-i^
step^ one^ instruction
(stepi) C-c^ C-f^
nish^ current^ stac
k^ frame^ (finish
M-c^
continue^ (cont) M-u^
up^ arg^ frames^ (up
M-d^
down^ arg^ frames
(down) C-x^ &^
copy^ numb^ er^ from
p^ oint,^ insert^ at
end
C-x^ SPC^
(in^ source^ le)^ set
break^ at^ p^ oint
GDB^ License show^ copying^
Display^ GNU^ General
Public^ License show^ warranty^
There^ is^ NO^ WARRANTY
for^ GDB. Display^ full^ no-w
arranty^ statemen
t.
Copyright^ c^ 1991,
1992 Free^ Softw
are^ Foundation,^ Inc. Roland^ Pesch^ (p^ esc
[email protected]),^ Jan
uary^ 1992|Revision:
The^ author^ assumes
no^ resp^ onsibility
for^ any^ errors^ on
this^ card.
This^ card^ may^ b
e^ freely^ distributed
under^ the^ terms
of^ the^ GNU
General^ Public^ License.Please^ contribute
to^ development^
of^ this^ card^ by^ annotating
it.
GDB^ itself^ is^ free
software;^ you^ are
welcome^ to^ distribute
copies^ of
it^ under^ the^ terms
of^ the^ GNU^ General
Public^ License.^
There^ is
absolutely^ no^ warran
ty^ for^ GDB.
