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 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.

OPTIONS

       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
           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-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.

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) 1988-2023 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."