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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | ENVIRONMENT | SEE ALSO | COPYRIGHT | COLOPHON |
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GDBSERVER(1) GNU Development Tools GDBSERVER(1)
gdbserver - Remote Server for the GNU Debugger
gdbserver comm prog [args...]
gdbserver --attach comm pid
gdbserver --multi comm
gdbserver is a program that allows you to run GDB on a different
machine than the one which is running the program being debugged.
Usage (server (target) side):
First, you need to have a copy of the program you want to debug
put onto the target system. The program can be stripped to save
space if needed, as gdbserver doesn't care about symbols. All
symbol handling is taken care of by the GDB running on the host
system.
To use the server, you log on to the target system, and run the
gdbserver program. You must tell it (a) how to communicate with
GDB, (b) the name of your program, and (c) its arguments. The
general syntax is:
target> gdbserver <comm> <program> [<args> ...]
For example, using a serial port, you might say:
target> gdbserver /dev/com1 emacs foo.txt
This tells gdbserver to debug emacs with an argument of foo.txt,
and to communicate with GDB via /dev/com1. gdbserver now waits
patiently for the host GDB to communicate with it.
To use a TCP connection, you could say:
target> gdbserver host:2345 emacs foo.txt
This says pretty much the same thing as the last example, except
that we are going to communicate with the "host" GDB via TCP. The
"host:2345" argument means that we are expecting to see a TCP
connection from "host" to local TCP port 2345. (Currently, the
"host" part is ignored.) You can choose any number you want for
the port number as long as it does not conflict with any existing
TCP ports on the target system. This same port number must be
used in the host GDBs "target remote" command, which will be
described shortly. Note that if you chose a port number that
conflicts with another service, gdbserver will print an error
message and exit.
gdbserver can also attach to running programs. This is
accomplished via the --attach argument. The syntax is:
target> gdbserver --attach <comm> <pid>
pid is the process ID of a currently running process. It isn't
necessary to point gdbserver at a binary for the running process.
To start "gdbserver" without supplying an initial command to run
or process ID to attach, use the --multi command line option. In
such case you should connect using "target extended-remote" to
start the program you want to debug.
target> gdbserver --multi <comm>
Usage (host side):
You need an unstripped copy of the target program on your host
system, since GDB needs to examine its symbol tables and such.
Start up GDB as you normally would, with the target program as the
first argument. (You may need to use the --baud option if the
serial line is running at anything except 9600 baud.) That is
"gdb TARGET-PROG", or "gdb --baud BAUD TARGET-PROG". After that,
the only new command you need to know about is "target remote" (or
"target extended-remote"). Its argument is either a device name
(usually a serial device, like /dev/ttyb), or a "HOST:PORT"
descriptor. For example:
(gdb) target remote /dev/ttyb
communicates with the server via serial line /dev/ttyb, and:
(gdb) target remote the-target:2345
communicates via a TCP connection to port 2345 on host
`the-target', where you previously started up gdbserver with the
same port number. Note that for TCP connections, you must start
up gdbserver prior to using the `target remote' command, otherwise
you may get an error that looks something like `Connection
refused'.
gdbserver can also debug multiple inferiors at once, described in
the GDB manual in node "Inferiors Connections and Programs" --
shell command "info -f gdb -n 'Inferiors Connections and
Programs'". In such case use the "extended-remote" GDB command
variant:
(gdb) target extended-remote the-target:2345
The gdbserver option --multi may or may not be used in such case.
There are three different modes for invoking gdbserver:
• Debug a specific program specified by its program name:
gdbserver <comm> <prog> [<args>...]
The comm parameter specifies how should the server communicate
with GDB; it is either a device name (to use a serial line), a
TCP port number (":1234"), or "-" or "stdio" to use
stdin/stdout of "gdbserver". Specify the name of the program
to debug in prog. Any remaining arguments will be passed to
the program verbatim. When the program exits, GDB will close
the connection, and "gdbserver" will exit.
• Debug a specific program by specifying the process ID of a
running program:
gdbserver --attach <comm> <pid>
The comm parameter is as described above. Supply the process
ID of a running program in pid; GDB will do everything else.
Like with the previous mode, when the process pid exits, GDB
will close the connection, and "gdbserver" will exit.
• Multi-process mode -- debug more than one program/process:
gdbserver --multi <comm>
In this mode, GDB can instruct gdbserver which command(s) to
run. Unlike the other 2 modes, GDB will not close the
connection when a process being debugged exits, so you can
debug several processes in the same session.
In each of the modes you may specify these options:
--help
List all options, with brief explanations.
--version
This option causes gdbserver to print its version number and
exit.
--attach
gdbserver will attach to a running program. The syntax is:
target> gdbserver --attach <comm> <pid>
pid is the process ID of a currently running process. It
isn't necessary to point gdbserver at a binary for the running
process.
--multi
To start "gdbserver" without supplying an initial command to
run or process ID to attach, use this command line option.
Then you can connect using "target extended-remote" and start
the program you want to debug. The syntax is:
target> gdbserver --multi <comm>
--debug[=option1,option2,...]
Instruct "gdbserver" to display extra status information about
the debugging process. This option is intended for
"gdbserver" development and for bug reports to the developers.
Each option is the name of a component for which debugging
should be enabled. The list of possible options is all,
threads, event-loop, remote. The special option all enables
all components. The option list is processed left to right,
and an option can be prefixed with the "-" character to
disable output for that component, so you could write:
target> gdbserver --debug=all,-event-loop
to turn on debug output for all components except event-loop.
If no options are passed to --debug then this is treated as
equivalent to --debug=threads. This could change in future
releases of "gdbserver".
--debug-file=filename
Instruct "gdbserver" to send any debug output to the given
filename. This option is intended for "gdbserver" development
and for bug reports to the developers.
--debug-format=option1[,option2,...]
Instruct "gdbserver" to include extra information in each line
of debugging output.
--wrapper
Specify a wrapper to launch programs for debugging. The
option should be followed by the name of the wrapper, then any
command-line arguments to pass to the wrapper, then "--"
indicating the end of the wrapper arguments.
--once
By default, gdbserver keeps the listening TCP port open, so
that additional connections are possible. However, if you
start "gdbserver" with the --once option, it will stop
listening for any further connection attempts after connecting
to the first GDB session.
The full 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
info gdb
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.
Copyright (c) 1988-2024 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License,
Version 1.3 or any later version published by the Free Software
Foundation; with the Invariant Sections being "Free Software" and
"Free Software Needs Free Documentation", with the Front-Cover
Texts being "A GNU Manual," and with the Back-Cover Texts as in
(a) below.
(a) The FSF's Back-Cover Text is: "You are free to copy and modify
this GNU Manual. Buying copies from GNU Press supports the FSF in
developing GNU and promoting software freedom."
This page is part of the gdb (GNU debugger) project. Information
about the project can be found at
⟨http://www.gnu.org/software/gdb/⟩. If you have a bug report for
this manual page, see ⟨http://www.gnu.org/software/gdb/bugs/⟩.
This page was obtained from the tarball gdb-16.3.tar.gz fetched
from ⟨https://ftp.gnu.org/gnu/gdb/⟩ on 2025-08-11. If you
discover any rendering problems in this HTML version of the page,
or you believe there is a better or more up-to-date source for the
page, or you have corrections or improvements to the information
in this COLOPHON (which is not part of the original manual page),
send a mail to [email protected]
gdb-16.3 2025-04-20 GDBSERVER(1)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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