How to link google protobuf libraries via cmake on linux? - c++

I'm trying to make it same way I made it for boost :
find_package(Boost COMPONENTS system filesystem REQUIRED)
find_package(ProtocolBuffers)
## Compiler flags
if(CMAKE_COMPILER_IS_GNUCXX)
set(CMAKE_CXX_FLAGS "-O2")
set(CMAKE_EXE_LINKER_FLAGS "-lsqlite3 -lrt -lpthread")
endif()
target_link_libraries(complex
${Boost_FILESYSTEM_LIBRARY}
${Boost_SYSTEM_LIBRARY}
${PROTOBUF_LIBRARY}
)
(googled it somewhere) but got bad output:
CMake Warning at complex/CMakeLists.txt:18 (find_package):
Could not find module FindProtocolBuffers.cmake or a configuration file for
package ProtocolBuffers.
Adjust CMAKE_MODULE_PATH to find FindProtocolBuffers.cmake or set
ProtocolBuffers_DIR to the directory containing a CMake configuration file
for ProtocolBuffers. The file will have one of the following names:
ProtocolBuffersConfig.cmake
protocolbuffers-config.cmake
How can I link it with cmake? or maybe I even can compile .proto file using cmake?

You could try CMake's FindProtobuf module:
include(FindProtobuf)
find_package(Protobuf REQUIRED)
include_directories(${PROTOBUF_INCLUDE_DIR})
...
target_link_libraries(complex
${Boost_FILESYSTEM_LIBRARY}
${Boost_SYSTEM_LIBRARY}
${PROTOBUF_LIBRARY}
)
For further info, run
cmake --help-module FindProtobuf

Spent a lot of time on this..
A. Different versions may require regeneration of cc files (obviously)
B. Different versions have different naming (PROTOBUF_LIBRARY vs. Protobuf_LIBRARIES)
Do note that the previous answer refers to view the FindProtobuf help which states the naming convention.
Also, Use '''message(STATUS "debug protobuf lib location:${PROTOBUF_LIBRARIES} '''
to debug.

Related

How to use Caffe library in C++ project with CMakeLists.txt

I'm trying to use Caffe in my C++ project which I compile with CMakeLists.txt, but it doesn't want to work. My only line in the code is
#include <caffe/caffe.hpp>
I compiled Caffe myself, it is installed in the directory "/home/tamas/caffe". My CMakeLists.txt looks like this so far:
cmake_minimum_required (VERSION 3.5)
include(FindPkgConfig)
project (main)
set (CMAKE_CXX_STANDARD 11)
set (CMAKE_CXX_STANDARD_REQUIRED TRUE)
set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Werror -std=c++11 -pthread")
set (source_dir "${PROJECT_SOURCE_DIR}/src/")
set (OpenCV_DIR "/home/tamas/opencv/include/opencv2")
set (Caffe_DIR "/home/tamas/caffe")
file (GLOB source_files "${source_dir}/ssd_video.cpp")
find_package(OpenCV 4.4.0 REQUIRED)
include_directories(${OpenCV_INCLUDE_DIRS})
find_package(Caffe REQUIRED)
include_directories(${Caffe_INCLUDE_DIRS})
add_executable (main ${source_files})
target_link_libraries(main ${OpenCV_LIBS})
target_link_libraries(main ${Caffe_LIBRARIES})
The error is the following:
CMake Error at CMakeLists.txt:24 (find_package):
By not providing "FindCaffe.cmake" in CMAKE_MODULE_PATH this project has
asked CMake to find a package configuration file provided by "Caffe", but
CMake did not find one.
Could not find a package configuration file provided by "Caffe" with any of
the following names:
CaffeConfig.cmake
caffe-config.cmake
Add the installation prefix of "Caffe" to CMAKE_PREFIX_PATH or set
"Caffe_DIR" to a directory containing one of the above files. If "Caffe"
provides a separate development package or SDK, be sure it has been
installed.
-- Configuring incomplete, errors occurred!
The problem is that I have searched and I don't have a FindCaffe.cmake file on my computer. I found an example for CaffeConfig.cmake, but I tried it and it doesn't work either.
Is there a way I can link Caffe with my C++ project? Thanks!
To fix this issue you may do the following:
Download this FindCAFFE.cmake file
Create cmake dir in your repo root directory and put the downloaded file there.
Modify your CMake file:
add set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${PROJECT_SOURCE_DIR}/cmake")
change set (Caffe_DIR "/home/tamas/caffe") to set (CAFFE_ROOT_DIR "/home/tamas/caffe")
change find_package(Caffe REQUIRED) to find_package(CAFFE REQUIRED)
use CAFFE_INCLUDE_DIRS and CAFFE_LIBRARIES for include directories and link libraries respectively
Clean up your build dir and run cmake command again
<library>_DIR should not be set manually in CMake code usually. There are better alternatives that should be used as setting these variable won't necessarily do what you want. It won't change where find_package finds its libraries.
The CaffeConfig.cmake file is generated when building Caffe. You should never download another one, these files are compatible only with a specific build configuration.
The Caffe library supports to be used with CMake, so FindCaffe.cmake is unnecessary.
For find_package to work, either set the <package>_ROOT variable (require CMake 3.12 minimum) or you must append the install path in CMAKE_PREFIX_PATH. Here's a CMake example that uses the prefix path:
# If you only built the library
list (APPEND CMAKE_PREFIX_PATH "/home/tamas/caffe/build-dir")
# If you installed the library there
list (APPEND CMAKE_PREFIX_PATH "/home/tamas/caffe/")
find_package(Caffe REQUIRED)
Note that the Caffe_LIBRARIES and Caffe_INCLUDE_DIRS won't be set. This is old CMake style and the Caffe library uses the new style. This is what you should do:
target_link_libraries(main PUBLIC caffe caffeproto)
This line add both include directory and adds linking to the libraries too.

Use libbitcoin in CLion

I am not a C++ programmer, only have made a course a while ago. Using homebrew I installed libbitcoin and was hoping that I can reference the library like I was able to reference the boost libraries. I also realized that there are no links in /usr/local/bin to the Cellar.
I think I could get it working by using the absolute paths but I am looking for the proper way of handling this constellation that I just mentioned.
Current CMake:
cmake_minimum_required(VERSION 2.8.4)
project(cplusplus)
message(STATUS "start running cmake...")
find_package(boost 1.65.1 COMPONENTS system filesystem REQUIRED)
find_package(libbitcoin 3.3.0 COMPONENTS system filesystem REQUIRED)
message("system: ${CMAKE_SYSTEM_PREFIX_PATH}")
find_library(LIB_BITCOIN libbitcoin)
message("bitcoin: ${LIB_BITCOIN}")
if(Boost_FOUND)
message(STATUS "Boost_INCLUDE_DIRS: ${Boost_INCLUDE_DIRS}")
message(STATUS "Boost_LIBRARIES: ${Boost_LIBRARIES}")
message(STATUS "Boost_VERSION: ${Boost_VERSION}")
include_directories(${Boost_INCLUDE_DIRS})
endif()
add_executable(cplusplus main.cpp)
if(Boost_FOUND)
target_link_libraries(cplusplus ${Boost_LIBRARIES})
endif()
Currently I get these errors:
/Applications/CLion.app/Contents/bin/cmake/bin/cmake -DCMAKE_BUILD_TYPE=Debug -G "CodeBlocks - Unix Makefiles" /Users/johndow/Documents/Workspace/bitcoin-code/cplusplus
-- start running cmake...
-- Boost version: 1.65.1
CMake Error at CMakeLists.txt:8 (find_package):
By not providing "Findlibbitcoin.cmake" in CMAKE_MODULE_PATH this project
has asked CMake to find a package configuration file provided by
"libbitcoin", but CMake did not find one.
Could not find a package configuration file provided by "libbitcoin"
(requested version 3.3.0) with any of the following names:
libbitcoinConfig.cmake
libbitcoin-config.cmake
Add the installation prefix of "libbitcoin" to CMAKE_PREFIX_PATH or set
"libbitcoin_DIR" to a directory containing one of the above files. If
"libbitcoin" provides a separate development package or SDK, be sure it has
been installed.
-- Configuring incomplete, errors occurred!
See also "/Users/johndoe/Documents/Workspace/bitcoin-code/cplusplus/cmake-build-debug/CMakeFiles/CMakeOutput.log".
[Finished]
You seem to have double lookup for libbitcoin library in your CMakeLists file. You are first looking for it by:
find_package(libbitcoin ...)
and then by
find_library(LIB_BITCOIN libbitcoin)
Cmake is not happy (as your error message says) with the find_package() clause as libbitcoin does not provide cmake configuration by itself. You have many ways how to fix it, just two of them:
remove find_package() and use only find_library(), I think this is the simpler way and your project should work this way
provide cmake configuration for libbitcoin by yourself. Good introduction how to do this is here (and good to read anyway):
https://cmake.org/Wiki/CMake:How_To_Find_Libraries
As far as I know, currently libbitcoin does not export any <libbitcoin>Config.cmake package.
But it does export a libbitcoin.pc file for generic use with pkg-config.
ie: /usr/local/lib/pkgconfig/libbitcoin.pc
If you get results from invoking pkg-config --cflags libbitcoin then it's there.
And then you can put something like this in your CMakeLists.txt:
#use this if libbitcoin is installed to some custom location
set(ENV{PKG_CONFIG_PATH} "/path/to/libbitcoin/pkgconfig/:$ENV{PKG_CONFIG_PATH}")
#then later..
find_package(PkgConfig REQUIRED)
pkg_check_modules(LIB_BITCOIN REQUIRED libbitcoin)
#then later..
target_link_libraries(${PROJECT_NAME} PRIVATE ${LIB_BITCOIN_LIBRARIES})
target_include_directories(${PROJECT_NAME} PRIVATE ${LIB_BITCOIN_INCLUDE_DIRS})
That should pull in boost, make the libbitcoin includes visible and solve all manner of compiler and linker woes.
(Or if you are feeling mad, you could always make use of this gist).

Can't use protobuf in cmakelists.txt

I am trying to run the example given in protobuf repo here, the c++ version. I have successfully installed the library and am able to run the Makefile. But on running the CMakeLists.txt, I get this error:
CMake Error at CMakeLists.txt:9 (find_package):
Could not find a package configuration file provided by "protobuf" with any
of the following names:
protobufConfig.cmake
protobuf-config.cmake
Add the installation prefix of "protobuf" to CMAKE_PREFIX_PATH or set
"protobuf_DIR" to a directory containing one of the above files. If
"protobuf" provides a separate development package or SDK, be sure it has
been installed.
-- Configuring incomplete, errors occurred!
See also "/home/cortana/Projects/CppProjects/proto/build/CMakeFiles/CMakeOutput.log".
See also "/home/cortana/Projects/CppProjects/proto/build/CMakeFiles/CMakeError.log".
I have updated my LD_LIBRARY_PATH but this error is still there. How do I remove this error?
EDIT:
CMakeLists.txt:
# Minimum CMake required
cmake_minimum_required(VERSION 2.8.12)
# Project
project(protobuf-examples)
include(FindProtobuf)
# Find required protobuf package
find_package(protobuf CONFIG REQUIRED)
if(protobuf_VERBOSE)
message(STATUS "Using Protocol Buffers ${Protobuf_VERSION}")
endif()
set(CMAKE_INCLUDE_CURRENT_DIR TRUE)
set(CMAKE_PREFIX_PATH
${CMAKE_PREFIX_PATH}
${THIRDPARTY_DIR}/protobuf-3.1.0
)
include_directories(${ProtobufIncludePath})
# http://www.cmake.org/Wiki/CMake_FAQ#How_can_I_build_my_MSVC_application_with_a_static_runtime.3F
if(MSVC AND protobuf_MSVC_STATIC_RUNTIME)
foreach(flag_var
CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE
CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELWITHDEBINFO)
if(${flag_var} MATCHES "/MD")
string(REGEX REPLACE "/MD" "/MT" ${flag_var} "${${flag_var}}")
endif(${flag_var} MATCHES "/MD")
endforeach()
endif()
foreach(example add_person list_people)
set(${example}_SRCS ${example}.cc)
set(${example}_PROTOS addressbook.proto)
#Code Generation
if(protobuf_MODULE_COMPATIBLE) #Legacy Support
protobuf_generate_cpp(${example}_PROTO_SRCS ${example}_PROTO_HDRS ${${example}_PROTOS})
list(APPEND ${example}_SRCS ${${example}_PROTO_SRCS} ${${example}_PROTO_HDRS})
else()
foreach(proto_file ${${example}_PROTOS})
get_filename_component(proto_file_abs ${proto_file} ABSOLUTE)
get_filename_component(basename ${proto_file} NAME_WE)
set(generated_files ${basename}.pb.cc ${basename}.pb.h)
list(APPEND ${example}_SRCS ${generated_files})
add_custom_command(
OUTPUT ${generated_files}
COMMAND protobuf::protoc
ARGS --cpp_out ${CMAKE_CURRENT_BINARY_DIR} -I ${CMAKE_CURRENT_SOURCE_DIR} ${proto_file_abs}
COMMENT "Generating ${generated_files} from ${proto_file}"
VERBATIM
)
endforeach()
endif()
#Executable setup
set(executable_name ${example}_cpp)
add_executable(${executable_name} ${${example}_SRCS} ${${example}_PROTOS})
if(protobuf_MODULE_COMPATIBLE) #Legacy mode
target_include_directories(${executable_name} PUBLIC ${PROTOBUF_INCLUDE_DIRS})
target_link_libraries(${executable_name} ${PROTOBUF_LIBRARIES})
else()
target_link_libraries(${executable_name} protobuf::libprotobuf)
endif()
endforeach()
EDIT 2:
After trying for 2 hours, I couldn't fix the CMakeLists.txt provided by google examples. I wrote this basic one and it works for me:
PROJECT(protopuff)
CMAKE_MINIMUM_REQUIRED (VERSION 3.5)
SET(CMAKE_CXX_FLAGS "-g -Wall -Werror -std=c++11")
INCLUDE(FindProtobuf)
FIND_PACKAGE(Protobuf REQUIRED)
INCLUDE_DIRECTORIES(${PROTOBUF_INCLUDE_DIR})
PROTOBUF_GENERATE_CPP(PROTO_SRC PROTO_HEADER addressbook.proto)
ADD_LIBRARY(proto ${PROTO_HEADER} ${PROTO_SRC})
INCLUDE_DIRECTORIES(${CMAKE_CURRENT_BINARY_DIR})
ADD_EXECUTABLE(${CMAKE_PROJECT_NAME}_add add_person.cc)
ADD_EXECUTABLE(${CMAKE_PROJECT_NAME}_list list_people.cc)
TARGET_LINK_LIBRARIES(${CMAKE_PROJECT_NAME}_add proto ${PROTOBUF_LIBRARY})
TARGET_LINK_LIBRARIES(${CMAKE_PROJECT_NAME}_list proto ${PROTOBUF_LIBRARY})
Your problem is here:
find_package(protobuf CONFIG REQUIRED)
The name should start with uppercase: Protobuf. And that is the reason why your version is working; because in there, you have used correct case (last code snippet line 6):
find_package(Protobuf REQUIRED)
Here cmake documentation for find_package
The command searches for a file called <name>Config.cmake or <lower-case-name>-config.cmake for each name specified.
in this thread fraser solved the problem but if you need to develop according to protobuf CMake config and find_package command in CMake for finding protobuf libraries. your protobuf library must be compiled with CMake and do not use configure routine .
after compile protobuf with CMake , a config file named protobuf-config.cmake will be generated into the prefix/lib/CMake/protobuf directory.
The CmakeList.txt that is provided by the OP works on Linux but it does NOT work on Windows.
There is a way to make the actual CMakeList.txt work without any changes. The problem is that it requires the CONFIG parameter and that part is not documented anywhere. We need to provide the path to that config using -Dprotobuf_DIR parameter while generating the project.
On Windows, wherever you have installed protobuf, it will have bin, cmake, include, lib folders. We need to give the path of this cmake folder as an argument, like following:
cmake -G "Visual Studio 16 2019" -A x64 -B _build2 -Dprotobuf_DIR=C:/protobuf/install/cmake
This will build a solution file in the current directory.

CMake user built libraries; cannot specify link libraries for target

I'm building a project in Cpp that will communicate with my Java apps via rabbitmq and post updates to twitter. I'm using a few libraries from github
rabbitmq-c
Rabbit installed to /usr/local/lib64
jansson - json library
I installed this a while back for another project, went to /usr/local/lib
twitcurl - C lib for Twitter API
Got installed to /usr/local/lib
If it matters, I'm using CLion as my IDE, which displays jansson and rabbit under auto-complete when defining includes - so that's picking the libs off my system somehow
e.g.
#include <jansson.h>
#include <amqp.h>
I link them using the target_link_libraries(name libs...) and I see output saying
build$ cmake ..
CMake Error at CMakeLists.txt:30 (target_link_libraries):
Cannot specify link libraries for target "twitcurl" which is not built by
this project.
I set LD_LIBRARY_PATH
export LD_LIBRARY_PATH=/usr/local/lib:/usr/local/lib64
I try to set the CMAKE_LIBRARY_PATH to include usr/local/lib and lib64 but doesn't seem to have any effect. Here's my CMakeLists.txt file
#
# This is a CMake makefile. You can find the cmake utility and
# information about it at http://www.cmake.org
#
cmake_minimum_required(VERSION 2.6)
set(PROJECT_NAME twitterUpdater)
set(SOURCE_FILES main.cpp)
set(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE)
set(CMAKE_LIBRARY_PATH ${CMAKE_LIBRARY_PATH} "/usr/local/lib"
"/usr/local/lib64")
project(${PROJECT_NAME})
find_package(X11 REQUIRED)
find_package(OpenCV REQUIRED)
IF (X11_FOUND)
INCLUDE_DIRECTORIES(${X11_INCLUDE_DIR})
LINK_LIBRARIES(${X11_LIBRARIES})
ENDIF ( X11_FOUND )
IF (OpenCV_FOUND)
include_directories(${OpenCV_INCLUDE_DIRS})
link_libraries(${OpenCV_LIBS})
ENDIF(OpenCV_FOUND)
add_executable(${PROJECT_NAME} ${SOURCE_FILES})
target_link_libraries(${project_name} twitcurl jansson rabbitmq)
What's confusing me is another project I have uses jansson by simply adding it here TARGET_LINK_LIBRARIES(${project_name} dlib jansson)
What did I miss?? Thanks
CMake variables are case sensitive, thus the variable ${project_name} results in an empty string. Use ${PROJECT_NAME} instead, i.e.:
target_link_libraries(${PROJECT_NAME} twitcurl jansson rabbitmq)
Running CMake with the flag --warn-uninitialized helps you detect mistakes like this.

how to include NTL using CMake

I use this line to compile a simple program:
g++ main.cc -lntl -lm -lgmp
How do you include this into CMake?
find_package(NTL REQUIRED)
find_package(GMP REQUIRED)
Doesn't work. And gives the following error:
CMake Error at CMakeLists.txt:30 (find_package):
Could not find module FindNTL.cmake or a configuration file for package
NTL.
...
.
and
SET(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} -std=c++0x -lntl -lm -lgmp)
Doesn't work either (but I think it's just wrong in general).
Thank you!
If ntl, m, and gmp libraries are usually installed to somewhere in the default path (e.g. /usr/ or /usr/local/), you could simply do something like:
cmake_minimum_required(VERSION 2.8 FATAL_ERROR)
project(Test)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++0x")
add_executable(test main.cc)
target_link_libraries(test ntl m gmp)
This is probably closest to your original g++ command, but it isn't very robust however; if any of the libraries aren't found, you won't know about it until you try linking. If you want to fail at configure time (i.e. while running CMake), you could add find_library calls for each of the required libs, e.g.
find_library(NTL_LIB ntl)
if(NOT NTL_LIB)
message(FATAL_ERROR "ntl library not found. Rerun cmake with -DCMAKE_PREFIX_PATH=\"<path to lib1>;<path to lib2>\"")
endif()
You'd then have to change your target_link_libraries command to
target_link_libraries(test ${NTL_LIB} ${M_LIB} ${GMP_LIB})
You'd probably also then have to do a find_file for one of each lib's header files to find out the appropriate path to add via the include_directories command (which translates to -I for g++).
Note, it's important to put quotes around the extra CXX_FLAGS arguments, or CMake treats them like separate values in a list and inserts a semi-colon between the flags.
For further information about find_library, find_file, etc. run:
cmake --help-command find_library
cmake --help-command find_file
Regarding your error:
It doesn't look like there's a FindNTL.cmake module included with CMake. That means you'll have to either:
Write your own FindNTL.cmake,
Find another that somebody else has written,
Hack together a solution that:
Checks if NTL is installed
Provides link targets, relevant flags, etc.
From a (rather quick) Google search, it appears somebody has an NTL module for CMake. Since NTL use GMP, you will probably need the associated GMP module for CMake. It doesn't look like a fully-featured CMake module, but it also appears to be the best thing out there (again, it was a quick Google search, and I don't use NTL).
To use, you'll want to add some things to your CMakeLists.txt:
# Let CMake know where you've put the FindNTL.cmake module.
set(CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/build/CMake/Modules")
# Call the FindNTL module:
find_package(NTL REQUIRED)
SET(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} -std=c++0x -lntl -lm -lgmp)
Yes, this is wrong. You don't want to be setting your CXX_FLAGS with linking directives. I would use:
SET ( CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} -std=cxx0x )
to set the Cxx standard you want to use. To actually link to libraries, you'll want to:
Ensure that you've found the libraries (with the relevant find_package ( FOO ) lines)
Link those against your target, like this:
# Build the Foo executable. (Or library, or whatever)
add_executable (FooEXE ${Foo_SOURCES} )
target_link_libraries (FooEXE
${bar_LIBRARIES}
${baz_LIBRARY}
)
Please note! ${bar_LIBRARIES} and ${baz_LIBRARY} is not a typo; there's no standard way of setting the relevant libraries in the FindFOO.cmake modules, which is, in my opinion, an annoyance. If one doesn't work, try the other, or, worst case, have a look in the relevant FindFOO.cmake file (there's a bunch installed with CMake by default) to see what each one uses. With the link i provided, you can use ${NTL_LIB} and ${GMP_LIB}.