vgdb(1) — Linux manual page


VGDB(1)                           vgdb                           VGDB(1)

NAME         top

       vgdb - intermediary between Valgrind and GDB or a shell

SYNOPSIS         top

       vgdb [options]

DESCRIPTION         top

       vgdb ("Valgrind to GDB") is used as an intermediary between
       Valgrind and GDB or a shell. It has three usage modes:

        1. As a standalone utility, it is used from a shell command line
           to send monitor commands to a process running under Valgrind.
           For this usage, the vgdb OPTION(s) must be followed by the
           monitor command to send. To send more than one command,
           separate them with the -c option.

        2. In combination with GDB "target remote |" command, it is used
           as the relay application between GDB and the Valgrind
           gdbserver. For this usage, only OPTION(s) can be given, but
           no COMMAND can be given.

        3. In the --multi mode, vgdb uses the extended remote protocol
           to communicate with GDB. This allows you to view output from
           both valgrind and GDB in the GDB session. This is
           accomplished via the "target extended-remote | vgdb --multi".
           In this mode you no longer need to start valgrind yourself.
           vgdb will start up valgrind when gdb tells it to run a new
           program. For this usage, the vgdb OPTIONS(s) can also include
           --valgrind and --vargs to describe how valgrind should be

OPTIONS         top

           Specifies the PID of the process to which vgdb must connect
           to. This option is useful in case more than one Valgrind
           gdbserver can be connected to. If the --pid argument is not
           given and multiple Valgrind gdbserver processes are running,
           vgdb will report the list of such processes and then exit.

           Must be given to both Valgrind and vgdb if you want to change
           the default prefix for the FIFOs (named pipes) used for
           communication between the Valgrind gdbserver and vgdb.

           Instructs vgdb to search for available Valgrind gdbservers
           for the specified number of seconds. This makes it possible
           start a vgdb process before starting the Valgrind gdbserver
           with which you intend the vgdb to communicate. This option is
           useful when used in conjunction with a --vgdb-prefix that is
           unique to the process you want to wait for. Also, if you use
           the --wait argument in the GDB "target remote" command, you
           must set the GDB remotetimeout to a value bigger than the
           --wait argument value. See option --max-invoke-ms (just
           below) for an example of setting the remotetimeout value.

           Gives the number of milliseconds after which vgdb will force
           the invocation of gdbserver embedded in Valgrind. The default
           value is 100 milliseconds. A value of 0 disables forced
           invocation. The forced invocation is used when vgdb is
           connected to a Valgrind gdbserver, and the Valgrind process
           has all its threads blocked in a system call.

           If you specify a large value, you might need to increase the
           GDB "remotetimeout" value from its default value of 2
           seconds. You should ensure that the timeout (in seconds) is
           bigger than the --max-invoke-ms value. For example, for
           --max-invoke-ms=5000, the following GDB command is suitable:

                   (gdb) set remotetimeout 6

           Instructs a standalone vgdb to exit if the Valgrind gdbserver
           it is connected to does not process a command in the
           specified number of seconds. The default value is to never
           time out.

           Instructs vgdb to use tcp/ip and listen for GDB on the
           specified port nr rather than to use a pipe to communicate
           with GDB. Using tcp/ip allows to have GDB running on one
           computer and debugging a Valgrind process running on another
           target computer. Example:

               # On the target computer, start your program under valgrind using
               valgrind --vgdb-error=0 prog
               # and then in another shell, run:
               vgdb --port=1234

           On the computer which hosts GDB, execute the command:

               gdb prog
               (gdb) target remote targetip:1234

           where targetip is the ip address or hostname of the target

           Makes vgdb start in extended-remote mode and to wait for gdb
           to tell us what to run.

           The path to valgrind to use, in extended-remote mode. If not
           specified, the system valgrind will be launched.

           Options to run valgrind with, in extended-remote mode. For
           example -q. Everything following --vargs will be provided as
           arguments to valgrind as is.

           To give more than one command to a standalone vgdb, separate
           the commands by an option -c. Example:

               vgdb v.set log_output -c leak_check any

           Instructs a standalone vgdb to report the list of the
           Valgrind gdbserver processes running and then exit.

           Instructs vgdb to add timestamps to vgdb information

           Instructs a standalone vgdb to show the state of the shared
           memory used by the Valgrind gdbserver. vgdb will exit after
           having shown the Valgrind gdbserver shared memory state.

           Instructs vgdb to produce debugging output. Give multiple -d
           args to increase the verbosity. When giving -d to a relay
           vgdb, you better redirect the standard error (stderr) of vgdb
           to a file to avoid interaction between GDB and vgdb debugging

SEE ALSO         top

       valgrind(1), $INSTALL/share/doc/valgrind/html/index.html or,

       Debugging your program using Valgrind's gdbserver and GDB[1]
       vgdb[2], Valgrind monitor commands[3].

AUTHOR         top

       Philippe Waroquiers.

NOTES         top

        1. Debugging your program using Valgrind's gdbserver and GDB

        2. vgdb

        3. Valgrind monitor commands

COLOPHON         top

       This page is part of the valgrind (a system for debugging and
       profiling Linux programs) project.  Information about the project
       can be found at ⟨⟩.  If you have a bug
       report for this manual page, see
       ⟨⟩.  This page
       was obtained from the project's upstream Git repository
       ⟨⟩ on 2023-12-22.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2023-12-17.)  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

Release 3.23.0.GIT             12/22/2023                        VGDB(1)