Hi , I have error during examinig simple publisher & subscriber (c++)

edit

I use groovy distribution & catkin first , I wrote the simple publisher & subscriber example that in beginner tutorials

then I tried to examine it following the following steps

• typing command roscore in catkin

• I made sure I have sourced my workspace's setup.sh file after calling catkin_make but before

trying to my applications:

>  In your catkin workspace
>      cd ~/catkin_ws    
>      source ./devel/setup.bash

• run the node talker using command

rosrun beginner_tutorials talker

but, when I typed command rosrun beginner_tutorials talker I recevied in output:

[rosrun] Couldn't find executable named talker below /home/eman/catkin_ws/src/beginner_tutorials

even though the node talker exists in the src of begibnner_turorials package & my CMakeLists.txt file looks like that:-

cmake_minimum_required(VERSION 2.8.3)
project(beginner_tutorials)

## Find catkin macros and libraries
find_package(catkin REQUIRED COMPONENTS roscpp rospy  std_msgs)

## Declare ROS messages and services ##

## Generate messages in the 'msg' folder
# add_message_files(  FILES  Message1.msg Message2.msg )

## Generate services in the 'srv' folder
# add_service_files(FILES Service1.srv Service2.srv )

## Generate added messages and services with any dependencies listed here
# generate_messages( DEPENDENCIES std_msgs )

## catkin specific configuration ##
###################################
## The catkin_package macro generates cmake config files for your package
## Declare things to be passed to dependent projects
## INCLUDE_DIRS: uncomment this if you package contains header files
## LIBRARIES: libraries you create in this project that dependent projects also need
## CATKIN_DEPENDS: catkin_packages dependent projects also need
## DEPENDS: system dependencies of this project that dependent projects also need
catkin_package(
#  INCLUDE_DIRS include
#  LIBRARIES beginner_tutorials
#  CATKIN_DEPENDS roscpp rospy std_msgs
#  DEPENDS system_lib
)

###########
## Build ##
###########

## Specify additional locations of header files
## Your package locations should be listed before other locations
# include_directories(include)
include_directories(
  ${catkin_INCLUDE_DIRS}
)

## Declare a cpp library
# add_library(beginner_tutorials
#   src/${PROJECT_NAME}/beginner_tutorials.cpp
# )

## Declare a cpp executable
# add_executable(beginner_tutorials_node src/beginner_tutorials_node.cpp)

## Add cmake target dependencies of the executable/library
## as an example, message headers may need to be generated before nodes
# add_dependencies(beginner_tutorials_node beginner_tutorials_generate_messages_cpp)

## Specify libraries to link a library or executable target against
# target_link_libraries(beginner_tutorials_node
#   ${catkin_LIBRARIES}
# ries(include ${catkin_INCLUDE_DIRS})

add_executable(talker src/talker.cpp)
target_link_libraries(talker ${catkin_LIBRARIES})

add_executable(listener src/listener.cpp)
target_link_libraries(listener ${catkin_LIBRARIES})



include_directories(include ${catkin_INCLUDE_DIRS})
add_executable(talker src/talker.cpp)
target_link_libraries(talker ${catkin_LIBRARIES})
add_executable(listener src/listener.cpp)
target_link_libraries(listener ${catkin_LIBRARIES})

any help,please

I wonder what is the reason for having that error??

• I made sure that Ros can find my
  package ( beginner_tutorials ) using command rospack find beginner_tutorials & it returns its path

/home/eman/catkin_ws/src/beginner_tutorials

so, that mean ros can see & find my package .

• I also made sure that the code of 2 nodes talker & listener exits in the src folder of my package

• , but when I tried to build the code using command catkin_make

1. typing 1st command cd ~/catkin_ws/src

2. then typing 2nd command catkin_make

I had that error :-

> The specified base path
> "/home/eman/catkin_ws/src" contains a
> CMakeLists.txt but "catkin_make" must
> be invoked in the root of workspace

I tried also

• 1-typing 1st command cd ~/catkin_ws

• 2- then typing 2nd command catkin_make

but, I had error

  CMake Error at /opt/ros/groovy/share/roscpp ...