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 it's 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.

       --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) 1988-2013 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-Red Hat Enterprise Linux 7.6.1-51.el7			    2014-06-10							      GDBSERVER(1)