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GDBSERVER(1)		     GNU Development Tools		  GDBSERVER(1)

NAME
       gdbserver - Remote Server for the GNU Debugger

SYNOPSIS
       gdbserver comm prog [args...]

       gdbserver --attach comm pid

       gdbserver --multi comm

DESCRIPTION
       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 and Programs" -- shell command "info -f
       gdb -n 'Inferiors 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.

OPTIONS
       There are three different modes for invoking gdbserver:

       o   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.

       o   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.

       o   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
	   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.

       --remote-debug
	   Instruct "gdbserver"	to display remote protocol debug output.  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.

SEE ALSO
       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
       Copyright (c) 1988-2019 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."

gdb-8.3.1.20191211-git		  2020-08-27			  GDBSERVER(1)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | SEE ALSO | COPYRIGHT

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