Linking C++ application to remoteApi.so fails on Ubuntu

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arthurnunesq
Posts: 4
Joined: 26 Mar 2016, 23:16

Linking C++ application to remoteApi.so fails on Ubuntu

Post by arthurnunesq » 11 Jul 2016, 21:11

Hello,

I'm building a VREP bridge ROS node, on Ubuntu 14.04, so a ROS application can connect to a VREP server running on a Windows machine.
However, when I tried to link my application to the "remoteApi.so" file distributed with VREP, I got the following error:

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/usr/bin/ld: cannot find -lremoteApi
My setup is as follows:
Ubuntu 14.04.1
ROS Indigo
I downloaded VREP and extracted it to "/opt/V-REP_PRO_EDU_V3_3_1_64_Linux".
My application is a simple ROS node:

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#include "ros/ros.h"
#include "std_msgs/String.h"

extern "C" {
    #include "extApi.h"
}


/**
 * This tutorial demonstrates simple receipt of messages over the ROS system.
 */
void chatterCallback(const std_msgs::String::ConstPtr& msg)
{
  ROS_INFO("I heard: [%s]", msg->data.c_str());
}

int main(int argc, char **argv)
{
	ros::init(argc, argv, "vrep_bridge");
	ros::NodeHandle n;
	ros::Subscriber sub = n.subscribe("chatter", 1000, chatterCallback);

	int port = 19997;

	int clientID=simxStart((simxChar*)"127.0.0.1",port,true,true,2000,5);
	if (clientID!=-1)
	{
		ROS_INFO("Connected to V-REP");
		simxFinish(clientID);
	}else{
		ROS_INFO("Could not connect to V-REP");
	}

	ros::spin();

	return 0;
}
In the CMakeLists.txt file, I've added the remoteApi include directory and linked directly to the ".so" file in the bindings directory, using its full path.

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cmake_minimum_required(VERSION 2.8.3)
project(vrep_bridge)

# Uncomment the line below to enable linker verbose output
# http://stackoverflow.com/a/21647591/702828
#set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Xlinker --verbose")

## Find catkin macros and libraries
## if COMPONENTS list like find_package(catkin REQUIRED COMPONENTS xyz)
## is used, also find other catkin packages
find_package(catkin REQUIRED COMPONENTS
  roscpp
  rospy
  std_msgs
  message_generation
)

## System dependencies are found with CMake's conventions
# find_package(Boost REQUIRED COMPONENTS system)


## Uncomment this if the package has a setup.py. This macro ensures
## modules and global scripts declared therein get installed
## See http://ros.org/doc/api/catkin/html/user_guide/setup_dot_py.html
# catkin_python_setup()

################################################
## Declare ROS messages, services and actions ##
################################################

## To declare and build messages, services or actions from within this
## package, follow these steps:
## * Let MSG_DEP_SET be the set of packages whose message types you use in
##   your messages/services/actions (e.g. std_msgs, actionlib_msgs, ...).
## * In the file package.xml:
##   * add a build_depend tag for "message_generation"
##   * add a build_depend and a run_depend tag for each package in MSG_DEP_SET
##   * If MSG_DEP_SET isn't empty the following dependency has been pulled in
##     but can be declared for certainty nonetheless:
##     * add a run_depend tag for "message_runtime"
## * In this file (CMakeLists.txt):
##   * add "message_generation" and every package in MSG_DEP_SET to
##     find_package(catkin REQUIRED COMPONENTS ...)
##   * add "message_runtime" and every package in MSG_DEP_SET to
##     catkin_package(CATKIN_DEPENDS ...)
##   * uncomment the add_*_files sections below as needed
##     and list every .msg/.srv/.action file to be processed
##   * uncomment the generate_messages entry below
##   * add every package in MSG_DEP_SET to generate_messages(DEPENDENCIES ...)

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

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

## Generate actions in the 'action' folder
# add_action_files(
#   FILES
#   Action1.action
#   Action2.action
# )

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

################################################
## Declare ROS dynamic reconfigure parameters ##
################################################

## To declare and build dynamic reconfigure parameters within this
## package, follow these steps:
## * In the file package.xml:
##   * add a build_depend and a run_depend tag for "dynamic_reconfigure"
## * In this file (CMakeLists.txt):
##   * add "dynamic_reconfigure" to
##     find_package(catkin REQUIRED COMPONENTS ...)
##   * uncomment the "generate_dynamic_reconfigure_options" section below
##     and list every .cfg file to be processed

## Generate dynamic reconfigure parameters in the 'cfg' folder
# generate_dynamic_reconfigure_options(
#   cfg/DynReconf1.cfg
#   cfg/DynReconf2.cfg
# )

###################################
## 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 vrep_bridge
#  CATKIN_DEPENDS roscpp rospy std_msgs
#  DEPENDS system_lib
  CATKIN_DEPENDS message_runtime
)

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

# VREP ======================================================================
if(NOT VREP_ROOT_DIR)
	set(VREP_ROOT_DIR $ENV{VREP_ROOT_DIR} CACHE PATH "Installation prefix for V-Rep." FORCE)
endif()
message(STATUS "including ${VREP_ROOT_DIR}/programming/include/")
message(STATUS "including ${VREP_ROOT_DIR}/programming/remoteApi/")

file(STRINGS ${VREP_ROOT_DIR}/readme.txt README_TXT LIMIT_COUNT 1)
string(REGEX MATCHALL "V([^\" ]+|\"[^\"]+\")" README_TXT "${README_TXT}")
string(REGEX MATCHALL "[0-9]" README_TXT "${README_TXT}")
list(GET README_TXT 0 VREP_VERSION_MAJOR)
list(GET README_TXT 1 VREP_VERSION_MINOR)
list(GET README_TXT 2 VREP_VERSION_PATCH)

message(STATUS "Using vrep version: ${VREP_VERSION_MAJOR}.${VREP_VERSION_MINOR}.${VREP_VERSION_PATCH}")

# VREP remoteApi shared object does not follow the correct naming standard ('libXXXX.so')
# and was not compiled with a SONAME. See link below.
# http://cmake.3232098.n2.nabble.com/linking-with-so-w-non-standard-names-td3441137.html
#set(CMAKE_PLATFORM_USES_PATH_WHEN_NO_SONAME FALSE) 
set(VREP_REMOTAPI ${VREP_ROOT_DIR}/programming/remoteApiBindings/lib/lib/64Bit/remoteApi.so)
# VREP ======================================================================


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

## Declare a C++ library
# add_library(vrep_bridge
#   src/${PROJECT_NAME}/vrep_bridge.cpp
# )

## Add cmake target dependencies of the library
## as an example, code may need to be generated before libraries
## either from message generation or dynamic reconfigure
# add_dependencies(vrep_bridge ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})

## Declare a C++ executable
# add_executable(vrep_bridge_node src/vrep_bridge_node.cpp)

## Add cmake target dependencies of the executable
## same as for the library above
# add_dependencies(vrep_bridge_node ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})

## Specify libraries to link a library or executable target against
# target_link_libraries(vrep_bridge_node
#   ${catkin_LIBRARIES}
# )

#############
## Install ##
#############

# all install targets should use catkin DESTINATION variables
# See http://ros.org/doc/api/catkin/html/adv_user_guide/variables.html

## Mark executable scripts (Python etc.) for installation
## in contrast to setup.py, you can choose the destination
# install(PROGRAMS
#   scripts/my_python_script
#   DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}
# )

## Mark executables and/or libraries for installation
# install(TARGETS vrep_bridge vrep_bridge_node
#   ARCHIVE DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
#   LIBRARY DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
#   RUNTIME DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}
# )

## Mark cpp header files for installation
# install(DIRECTORY include/${PROJECT_NAME}/
#   DESTINATION ${CATKIN_PACKAGE_INCLUDE_DESTINATION}
#   FILES_MATCHING PATTERN "*.h"
#   PATTERN ".svn" EXCLUDE
# )

## Mark other files for installation (e.g. launch and bag files, etc.)
# install(FILES
#   # myfile1
#   # myfile2
#   DESTINATION ${CATKIN_PACKAGE_SHARE_DESTINATION}
# )

#############
## Testing ##
#############

## Add gtest based cpp test target and link libraries
# catkin_add_gtest(${PROJECT_NAME}-test test/test_vrep_bridge.cpp)
# if(TARGET ${PROJECT_NAME}-test)
#   target_link_libraries(${PROJECT_NAME}-test ${PROJECT_NAME})
# endif()

## Add folders to be run by python nosetests
# catkin_add_nosetests(test)

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

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

add_executable(vrep_bridge src/vrep_bridge.cpp)
target_link_libraries(vrep_bridge ${catkin_LIBRARIES} ${VREP_REMOTAPI})
add_dependencies(vrep_bridge vrep_bridge_generate_messages_cpp)

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


Following the information available in this post, I was able to find two solutions for this problem:
1- Rename the ".../programming/remoteApiBindings/lib/lib/64Bit/remoteApi.so" to "libremoteApi.so".
2- Add the following line before "target_link_libraries"

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set(CMAKE_PLATFORM_USES_PATH_WHEN_NO_SONAME FALSE) 
The mentioned post indicates that the shared library should have been named following the correct standard ("libXXX.so") or compiled with the SONAME option set correctly. The way it is now, it requires the fixes mentioned before so it can be linked correctly.

Cheers,

Arthur Queiroz

coppelia
Site Admin
Posts: 6736
Joined: 14 Dec 2012, 00:25

Re: Linking C++ application to remoteApi.so fails on Ubuntu

Post by coppelia » 12 Jul 2016, 20:11

Hello Arthur,

thanks for the info.
In your case however, you could also have directly included the remote API source code into your application, instead of linking to the remote API library.

Cheers

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