I couldn't reproduce but it seems like you have more than one installation of ddynamic_reconfigure on your machine. realsense-viewer would not care since it's not using it.

Could not find more than one install of ddynamic_reconfigure, but a complete wipe and reinstall of the system fixed the issue.

I also bumped into this error and the problem was that in the steps when installing the realsense2-camera (following the .travis.yml), when you have to do:

catkin_make clean
catkin_make -DCATKIN_ENABLE_TESTING=False -DCMAKE_BUILD_TYPE=Release
catkin_make install

I had skipped to do the last step catkin_make install. Just in case someone else bumps into this

Edit: see #838 (comment)
Hello!

I'm facing similar issue here, but a manual clean of ros_workspace didn't help.
Here is my undefined symbol :
librealsense2_camera.so: undefined symbol: _ZN20ddynamic_reconfigure19DDynamicReconfigure16registerVariableIiEEvRKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEET_RKN5boost8functionIFvSA_EEES9_SA_SA_
Seems indeed linked to ddynamic reconfigure but ... can't figure out how to deal with that.

@doronhi , could you please tell me a little more about this ?? :

I couldn't reproduce but it seems like you have more than one installation of ddynamic_reconfigure on your machine. realsense-viewer would not care since it's not using it.

Thanks a lot !

Hello!

I'm facing similar issue here, but a manual clean of ros_workspace didn't help.
Here is my undefined symbol :
librealsense2_camera.so: undefined symbol: _ZN20ddynamic_reconfigure19DDynamicReconfigure16registerVariableIiEEvRKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEET_RKN5boost8functionIFvSA_EEES9_SA_SA_
Seems indeed linked to ddynamic reconfigure but ... can't figure out how to deal with that.

@doronhi , could you please tell me a little more about this ?? :

I couldn't reproduce but it seems like you have more than one installation of ddynamic_reconfigure on your machine. realsense-viewer would not care since it's not using it.

Thanks a lot !

If someone encounter this issue : I was indeed compiling in a "not clean, polluted by old build artifact which was using old librealsense version" build environment. But catkin clean is not sufficient, I had to reinstall everything from scratch, don't know why...

hey im having similar issue on a intel x64 notebook PC running ubuntu 16.04
The realsense viewer is running with 2.42.0 build and it works well
I downloaded the ROS1 version of the 2.42.0 supported package 2.2.22. But end up with this error.

I tried to uninstall apt remove ddynamic * and download the 0.2.0 version from github. But encoutner with build error says the register function not compatiable. I searched in the header file. it was there.

So i have no idea whats going on.

And why it is looking for library at /devel/lib//librealsense2_camera.so: undefined symbol: why with \ ?

Samething happens if i use both apt based realsense 2 and ddynamic reconfig

Ok my problem solved.

In my file system

There is
catkin_ws
driver_ws
deply_ws
test_ws

There was one unknown version of ddynamic in test_ws and it was included automatically in bashrc. remove all possible ddynamic solved it.

Ok my problem solved.

In my file system

There is
catkin_ws
driver_ws
deply_ws
test_ws

There was one unknown version of ddynamic in test_ws and it was included automatically in bashrc. remove all possible ddynamic solved it.

If you don't mind can you please elaborate how to solve this issue? I am facing same problem. Actually I am little bit new to ROS so can you please explain in little detail how to solve this, i will be very much thankful to you. I am facing this

Ok my problem solved.
In my file system
There is
catkin_ws
driver_ws
deply_ws
test_ws
There was one unknown version of ddynamic in test_ws and it was included automatically in bashrc. remove all possible ddynamic solved it.

If you don't mind can you please elaborate how to solve this issue? I am facing same problem. Actually I am little bit new to ROS so can you please explain in little detail how to solve this, i will be very much thankful to you. I am facing this

i got duplicated build library. Just delete all source in the bashrc and remove all catkin_ws. THen with a clean build and src. then try to build again. This is to make sure that the library is not linked to the wrong version of supporting library ddynamic.

I tried multiple version to isolate the problem in ddynamic. So for your case, if the solution i said earlier didn`t work out. You can try 43 and 42 and and default ubuntu apt install. see whats the error coming out

Ok my problem solved.
In my file system
There is
catkin_ws
driver_ws
deply_ws
test_ws
There was one unknown version of ddynamic in test_ws and it was included automatically in bashrc. remove all possible ddynamic solved it.

If you don't mind can you please elaborate how to solve this issue? I am facing same problem. Actually I am little bit new to ROS so can you please explain in little detail how to solve this, i will be very much thankful to you. I am facing this

i got duplicated build library. Just delete all source in the bashrc and remove all catkin_ws. THen with a clean build and src. then try to build again. This is to make sure that the library is not linked to the wrong version of supporting library ddynamic.

I tried multiple version to isolate the problem in ddynamic. So for your case, if the solution i said earlier didn`t work out. You can try 43 and 42 and and default ubuntu apt install. see whats the error coming out

Got it, Thank you so much brother

I faced similar problem as following:

/opt/ros/melodic/lib/nodelet/nodelet: symbol lookup error: /home/jungle/catkin_my_ws/devel/lib//librealsense2_camera.so: undefined symbol: _ZN14image_geometry18PinholeCameraModelC1Ev

I solved it by adding the package "image_geometry" to CMakeLists.txt:

I hope you drawing inspiration from my method!

Thanks Got it.

thank you, snakehaihai!

my ~/.bashrc had second line of source /opt/ros/melodic/setup.bash and extraneous lines of PATH=/home/***/bin:$PATH that were causing issues.

I followed the above steps , then also getting the same error here is my .bashrc

# ~/.bashrc: executed by bash(1) for non-login shells.
# see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
# for examples

# If not running interactively, don't do anything
case $- in
    *i*) ;;
      *) return;;
esac

# don't put duplicate lines or lines starting with space in the history.
# See bash(1) for more options
HISTCONTROL=ignoreboth

# append to the history file, don't overwrite it
shopt -s histappend

# for setting history length see HISTSIZE and HISTFILESIZE in bash(1)
HISTSIZE=1000
HISTFILESIZE=2000

# check the window size after each command and, if necessary,
# update the values of LINES and COLUMNS.
shopt -s checkwinsize

# If set, the pattern "**" used in a pathname expansion context will
# match all files and zero or more directories and subdirectories.
#shopt -s globstar

# make less more friendly for non-text input files, see lesspipe(1)
[ -x /usr/bin/lesspipe ] && eval "$(SHELL=/bin/sh lesspipe)"

# set variable identifying the chroot you work in (used in the prompt below)
if [ -z "${debian_chroot:-}" ] && [ -r /etc/debian_chroot ]; then
    debian_chroot=$(cat /etc/debian_chroot)
fi

# set a fancy prompt (non-color, unless we know we "want" color)
case "$TERM" in
    xterm-color|*-256color) color_prompt=yes;;
esac

# uncomment for a colored prompt, if the terminal has the capability; turned
# off by default to not distract the user: the focus in a terminal window
# should be on the output of commands, not on the prompt
#force_color_prompt=yes

if [ -n "$force_color_prompt" ]; then
    if [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then
	# We have color support; assume it's compliant with Ecma-48
	# (ISO/IEC-6429). (Lack of such support is extremely rare, and such
	# a case would tend to support setf rather than setaf.)
	color_prompt=yes
    else
	color_prompt=
    fi
fi

if [ "$color_prompt" = yes ]; then
    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
else
    PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
fi
unset color_prompt force_color_prompt

# If this is an xterm set the title to user@host:dir
case "$TERM" in
xterm*|rxvt*)
    PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1"
    ;;
*)
    ;;
esac

# enable color support of ls and also add handy aliases
if [ -x /usr/bin/dircolors ]; then
    test -r ~/.dircolors && eval "$(dircolors -b ~/.dircolors)" || eval "$(dircolors -b)"
    alias ls='ls --color=auto'
    #alias dir='dir --color=auto'
    #alias vdir='vdir --color=auto'

    alias grep='grep --color=auto'
    alias fgrep='fgrep --color=auto'
    alias egrep='egrep --color=auto'
fi

# colored GCC warnings and errors
#export GCC_COLORS='error=01;31:warning=01;35:note=01;36:caret=01;32:locus=01:quote=01'

# some more ls aliases
alias ll='ls -alF'
alias la='ls -A'
alias l='ls -CF'

# Add an "alert" alias for long running commands.  Use like so:
#   sleep 10; alert
alias alert='notify-send --urgency=low -i "$([ $? = 0 ] && echo terminal || echo error)" "$(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/[;&|]\s*alert$//'\'')"'

# Alias definitions.
# You may want to put all your additions into a separate file like
# ~/.bash_aliases, instead of adding them here directly.
# See /usr/share/doc/bash-doc/examples in the bash-doc package.

if [ -f ~/.bash_aliases ]; then
    . ~/.bash_aliases
fi

# enable programmable completion features (you don't need to enable
# this, if it's already enabled in /etc/bash.bashrc and /etc/profile
# sources /etc/bash.bashrc).
if ! shopt -oq posix; then
  if [ -f /usr/share/bash-completion/bash_completion ]; then
    . /usr/share/bash-completion/bash_completion
  elif [ -f /etc/bash_completion ]; then
    . /etc/bash_completion
  fi
fi

I followed the above steps , then also getting the same error here is my .bashrc

# ~/.bashrc: executed by bash(1) for non-login shells.
# see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
# for examples

# If not running interactively, don't do anything
case $- in
    *i*) ;;
      *) return;;
esac

# don't put duplicate lines or lines starting with space in the history.
# See bash(1) for more options
HISTCONTROL=ignoreboth

# append to the history file, don't overwrite it
shopt -s histappend

# for setting history length see HISTSIZE and HISTFILESIZE in bash(1)
HISTSIZE=1000
HISTFILESIZE=2000

# check the window size after each command and, if necessary,
# update the values of LINES and COLUMNS.
shopt -s checkwinsize

# If set, the pattern "**" used in a pathname expansion context will
# match all files and zero or more directories and subdirectories.
#shopt -s globstar

# make less more friendly for non-text input files, see lesspipe(1)
[ -x /usr/bin/lesspipe ] && eval "$(SHELL=/bin/sh lesspipe)"

# set variable identifying the chroot you work in (used in the prompt below)
if [ -z "${debian_chroot:-}" ] && [ -r /etc/debian_chroot ]; then
    debian_chroot=$(cat /etc/debian_chroot)
fi

# set a fancy prompt (non-color, unless we know we "want" color)
case "$TERM" in
    xterm-color|*-256color) color_prompt=yes;;
esac

# uncomment for a colored prompt, if the terminal has the capability; turned
# off by default to not distract the user: the focus in a terminal window
# should be on the output of commands, not on the prompt
#force_color_prompt=yes

if [ -n "$force_color_prompt" ]; then
    if [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then
	# We have color support; assume it's compliant with Ecma-48
	# (ISO/IEC-6429). (Lack of such support is extremely rare, and such
	# a case would tend to support setf rather than setaf.)
	color_prompt=yes
    else
	color_prompt=
    fi
fi

if [ "$color_prompt" = yes ]; then
    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
else
    PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
fi
unset color_prompt force_color_prompt

# If this is an xterm set the title to user@host:dir
case "$TERM" in
xterm*|rxvt*)
    PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1"
    ;;
*)
    ;;
esac

# enable color support of ls and also add handy aliases
if [ -x /usr/bin/dircolors ]; then
    test -r ~/.dircolors && eval "$(dircolors -b ~/.dircolors)" || eval "$(dircolors -b)"
    alias ls='ls --color=auto'
    #alias dir='dir --color=auto'
    #alias vdir='vdir --color=auto'

    alias grep='grep --color=auto'
    alias fgrep='fgrep --color=auto'
    alias egrep='egrep --color=auto'
fi

# colored GCC warnings and errors
#export GCC_COLORS='error=01;31:warning=01;35:note=01;36:caret=01;32:locus=01:quote=01'

# some more ls aliases
alias ll='ls -alF'
alias la='ls -A'
alias l='ls -CF'

# Add an "alert" alias for long running commands.  Use like so:
#   sleep 10; alert
alias alert='notify-send --urgency=low -i "$([ $? = 0 ] && echo terminal || echo error)" "$(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/[;&|]\s*alert$//'\'')"'

# Alias definitions.
# You may want to put all your additions into a separate file like
# ~/.bash_aliases, instead of adding them here directly.
# See /usr/share/doc/bash-doc/examples in the bash-doc package.

if [ -f ~/.bash_aliases ]; then
    . ~/.bash_aliases
fi

# enable programmable completion features (you don't need to enable
# this, if it's already enabled in /etc/bash.bashrc and /etc/profile
# sources /etc/bash.bashrc).
if ! shopt -oq posix; then
  if [ -f /usr/share/bash-completion/bash_completion ]; then
    . /usr/share/bash-completion/bash_completion
  elif [ -f /etc/bash_completion ]; then
    . /etc/bash_completion
  fi
fi

your bashrc has no source. you didnt source the ros in /opt and didnt source the ros in the ws. follow ros install and get the following two lines inside

echo "source /opt/ros/melodic/setup.bash" >> ~/.bashrc
source ~/.bashrc

also if you have workspace do the same