The GNU Debugger
[-nh] [-nx] [-q]
[-f] [-b bps]
symfile] [-e prog]
[-se prog] [-c core]
[-x file] [-ex cmd]
[-d dir] [prog
[options] --args prog
add an example, a script, a trick and tips
gdb ./DarwinStreamingServer -x gdb_script
gdb -command "ews_init.gdb" bootimg;
GDB debugging tool for linux
First of all if you don't have a core dumped on your disk is
because often by default the core size is limited to 0 byte, thus
core are not dumped.
To check this and correct it, simply perform this in your shell
just before running your program (in the same shell):
ulimit -c unlimited
The first command will give you the limit size for core files,
the second one will make it unlimited.
Now you can run your program and it will dump a core upon
segmentation fault. You still need GDB though.
GDB is an installable package that come with the Red Hat
installation DVDs. Red Hat offers a nice and simple interface to
do this, check their online manual. Search for GDB, selct it
and click Apply. It will request to insert the installation DVD.
sending one key stroke to two windows (Ubuntu)
I don't see an easy way to do this while inside one of your
debugging windows, but you could use a third windows running a
script that wrapped around xvkbd. It's in the ubuntu repository (might be in
universe). The script could read your keyboard input and then
call xvkbd twice, sending the keystrokes to both windows.
Normally a graphical program, using
xvkbd -window xterm2 -text $foo
sends key events to specific windows, but doesn't invoke a UI.
You also might find that wmctrl helps identify windows & stuff. A
simplistic script might be:
while [ 1 ]; do
wmctrl -i -a 0x02200003 #forcibly set focus in window running script
xvkbd -window 0x2202ea4 -text "$keys\r"
xvkbd -window 0x2200084 -text "$keys\r"
Why gdb is bind to fixed version of autoconf?
Not specific to
gdb, an explanation (along with
possible solutions) is here.
How to know if gdb is installed?
If GDB is installed then it will display all the available
options within your GDB.
The purpose of
a debugger such as GDB is to allow you to see what is going
on ’’inside’’ another program while
it executes—or what another program was doing at the
moment it crashed.
GDB can do four
main kinds of things (plus other things in support of these)
to help you catch bugs in the act:
Start your program, specifying
anything that might affect its behavior.
Make your program stop on specified conditions.
Examine what has happened, when your program has
Change things in your program, so you can experiment
with correcting the effects of one bug and go on to learn
You can use GDB
to debug programs written in C, C++, and Modula-2. Fortran
support will be added when a GNU Fortran compiler is
GDB is invoked
with the shell command gdb. Once started, it reads
commands from the terminal until you tell it to exit with
the GDB command quit. You can get online help from
gdb itself by using the command help.
You can run
gdb with no arguments or options; but the most usual
way to start GDB is with one argument or two, specifying an
executable program as the argument:
You can also
start with both an executable program and a core file
gdb program core
instead, specify a process ID as a second argument, if you
want to debug a running process:
gdb program 1234
GDB to process 1234 (unless you also have a file
named ’1234’; GDB does check for a core
Here are some
of the most frequently needed GDB commands:
Set a breakpoint at
function (in file).
Start your program (with
arglist, if specified).
Backtrace: display the program stack.
Display the value of an
Continue running your program (after stopping, e.g. at a
Execute next program line (after stopping); step
over any function calls in the line.
look at the program line where
it is presently stopped.
type the text of the program in
the vicinity of where it is presently stopped.
Execute next program line (after stopping); step
into any function calls in the line.
Show information about GDB
command name, or general information about using
details on GDB, see Using GDB: A Guide to the GNU
Source-Level Debugger, by Richard M. Stallman and Roland
H. Pesch. The same text is available online as the
gdb entry in the info program.
other than options specify an executable file and core file
(or process ID); that is, the first argument encountered
with no associated option flag is equivalent to a
’-se’ option, and the second, if
any, is equivalent to a ’-c’ option
if it’s the name of a file. Many options have both
long and short forms; both are shown here. The long forms
are also recognized if you truncate them, so long as enough
of the option is present to be unambiguous. (If you prefer,
you can flag option arguments with ’+’
rather than ’-’, though we
illustrate the more usual convention.)
All the options
and command line arguments you give are processed in
sequential order. The order makes a difference when the
’-x’ option is used.
List all options, with brief explanations.
Read symbol table from file
Enable writing into executable and core files.
Use file file as the
executable file to execute when appropriate, and for
examining pure data in conjunction with a core dump.
Read symbol table from file
file and use it as the executable file.
Use file file as a core
dump to examine.
Execute GDB commands from file
Execute given GDB
Add directory to the
path to search for source files.
Do not execute commands from ~/.gdbinit.
Do not execute commands from any
’.gdbinit’ initialization files.
’’Quiet’’. Do not print the
introductory and copyright messages. These messages are also
suppressed in batch mode.
Run in batch mode. Exit with status 0 after
processing all the command files specified with
’.gdbinit’, if not inhibited). Exit with
nonzero status if an error occurs in executing the GDB
commands in the command files.
Batch mode may
be useful for running GDB as a filter, for example to
download and run a program on another computer; in order to
make this more useful, the message
Program exited normally.
ordinarily issued whenever a program running under GDB
control terminates) is not issued when running in batch
Run GDB using directory
as its working directory, instead of the current
Emacs sets this option when it runs GDB as a subprocess.
It tells GDB to output the full file name and line number in
a standard, recognizable fashion each time a stack frame is
displayed (which includes each time the program stops). This
recognizable format looks like two ’ 32’
characters, followed by the file name, line number and
character position separated by colons, and a newline. The
Emacs-to-GDB interface program uses the two ’
32’ characters as a signal to display the
source code for the frame.
Set the line speed (baud rate or bits per second) of any
serial interface used by GDB for remote debugging.
Run using device for
your program’s standard input and output.
Pass arguments after the program name to the
program when it is run.
Run GDB using a text (console) user interface.
Copyright (c) 1991, 2010 Free Software Foundation, Inc.
Permission is granted to make and distribute verbatim copies of
this manual provided the copyright notice and this permission
notice are preserved on all copies.
Permission is granted to copy and distribute modified versions of
this manual under the conditions for verbatim copying, provided
that the entire resulting derived work is distributed under the
terms of a permission notice identical to this one.
Permission is granted to copy and distribute translations of this
manual into another language, under the above conditions for
modified versions, except that this permission notice may be
included in translations approved by the Free Software Foundation
instead of in the original English.
documentation for gdb is maintained as a Texinfo
manual. If the info and gdb programs and
GDB’s Texinfo documentation are properly installed at
your site, the command
should give you
access to the complete manual.
Using GDB: A
Guide to the GNU Source-Level Debugger, Richard M.
Stallman and Roland H. Pesch, July 1991.