Integration with a Build System

[MichaelBMiner]

Hello,

I am using your repo as a part of my Yocto Linux image. I am getting conflicts as DBCPPP and the device image both attempt to install /usr/lib/libxml2.so.2.9.10. I wrote a full bit on stack overflow.

In your CMakeLists.txt you add the LibXML2 from the third-party folder. I am wondering how can I edit the CMakeLists file to use the libxml2 provided by my linux image.

In my image I also have boost.
/mnt/WorkDrive/Documents/EVCC_Application/build-fb/tmp/work/cortexa7t2hf-neon-poky-linux-gnueabi/libxml2/2.9.10-r0
/mnt/WorkDrive/Documents/EVCC_Application/build-fb/tmp/work/cortexa7t2hf-neon-poky-linux-gnueabi/boost

I would like to use these instead of the third party folder.

[MichaelBMiner]

I think there are two options here.

1. Do not build LibXML2 and have your CMakeLists.txt include it from my sources
2. Do not install LibXML2

I have attempted to do this but my understanding of CMake has been a challenge.

[xR3b0rn]

I think it would be nice to have some flag in the CMakeLists.txt to either build it with dbcppp or to use intalled source from somewher ein the system.

[MichaelBMiner]

include(FindPkgConfig)
include(FindLibXml2 REQUIRED)
message(STATUS, ${LIBXML2_INCLUDE_DIR})

This returns /usr/local/include/libxml2. So I am understanding how I can use this, but not how I find my version of it in the /mnt/WorkDrive/.... folder

[MichaelBMiner]

Got a step further but I unsure what to put in place of target_link_libraries(libxmlmm LibXml2) and install(TARGETS "libxmlmm" "LibXml2" EXPORT ${PROJECT_NAME}Targets DESTINATION ${CMAKE_INSTALL_LIBDIR})

I can properly set the Lib2Xml2 using

include(FindPkgConfig)
include(FindLibXml2 REQUIRED)
set(LIBXML2_INCLUDE_DIR /mnt/WorkDrive/Documents/EVCC_Application/build-fb/tmp/work/cortexa7t2hf-neon-poky-linux-gnueabi/libxml2/2.9.10-r0/libxml2-2.9.10/include)
set(LIBXML2_LIBRARIES /mnt/WorkDrive/Documents/EVCC_Application/build-fb/tmp/work/cortexa7t2hf-neon-poky-linux-gnueabi/libxml2/2.9.10-r0/image/usr/lib)

[xR3b0rn]

The proper way to use the LIBXML2_INCLUDE_DIR and LIBXML2_LIBRARIES is to pass these variables via the cmake command:

cmake -DLIBXML2_INCLUDE_DIR=/mnt/WorkDrive/Documents/EVCC_Application/build-fb/tmp/work/cortexa7t2hf-neon-poky-linux-gnueabi/libxml2/2.9.10-r0/libxml2-2.9.10/include -DLIBXML2_LIBRARIES=/mnt/WorkDrive/Documents/EVCC_Application/build-fb/tmp/work/cortexa7t2hf-neon-poky-linux-gnueabi/libxml2/2.9.10-r0/image/usr/lib <dbcpp-dir>

[MichaelBMiner]

Is there no way to do this from within the CMakeLists.txt file? I do not call cmake from the Yocto build. It calls cmake on its own with no additional parameters.

[MichaelBMiner]

I took your suggestion and combined it with your build instructions. I get a proper output. When I run make. I get the same error. fatal error: libxml/tree.h: No such file or directory. It seems I am still not properly linking the library.

cmake -DLIBXML2_INCLUDE_DIR=/mnt/WorkDrive/Documents/EVCC_Application/build-fb/tmp/work/cortexa7t2hf-neon-poky-linux-gnueabi/libxml2/2.9.10-r0/libxml2-2.9.10/include -DLIBXML2_LIBRARIES=/mnt/WorkDrive/Documents/EVCC_Application/build-fb/tmp/work/cortexa7t2hf-neon-poky-linux-gnueabi/libxml2/2.9.10-r0/image/usr/lib -DCMAKE_BUILD_TYPE=Release ..

[MichaelBMiner]

Getting ready to head out for the day. But progress! Using the cmake above and the following CMakeLists.txt file.

cmake_minimum_required(VERSION 3.12)

#set(LIBXML2_INCLUDE_DIR /mnt/WorkDrive/Documents/EVCC_Application/build-fb/tmp/work/cortexa7t2hf-neon-poky-linux-gnueabi/libxml2/2.9.10-r0/libxml2-2.9.10/include)
#set(LIBXML2_LIBRARIES /mnt/WorkDrive/Documents/EVCC_Application/build-fb/tmp/work/cortexa7t2hf-neon-poky-linux-gnueabi/libxml2/2.9.10-r0/image/usr/lib)

SET(CMAKE_FIND_LIBRARY_PREFIXES "lib")
SET(CMAKE_FIND_LIBRARY_SUFFIXES ".so" ".a")

include(FindPkgConfig)
include(FindLibXml2 REQUIRED)

project("libdbcppp" VERSION 0.1.0)

option(build_tests "Build tests" ON)
option(build_examples "Build examples" ON)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_STATIC_LIBRARY_PREFIX "")
set(CMAKE_SHARED_LIBRARY_PREFIX "")
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)

if (CMAKE_CXX_COMPILER_ID MATCHES "MSVC")
	add_definitions("/bigobj")
endif()

include_directories("include")
include_directories("third-party/libxmlmm/libxmlmm")
include_directories("/mnt/WorkDrive/Documents/EVCC_Application/build-fb/tmp/work/cortexa7t2hf-neon-poky-linux-gnueabi/boost")
include_directories("/mnt/WorkDrive/Documents/EVCC_Application/build-fb/tmp/work/cortexa7t2hf-neon-poky-linux-gnueabi/libxml2/2.9.10-r0/libxml2-2.9.10/include")
include_directories("third-party/cxxopts/include")

file(GLOB libxmlmm_header
    "third-party/libxmlmm/libxmlmm/*.h"
)
file(GLOB libxmlmm_src
    "third-party/libxmlmm/libxmlmm/*.cpp"
)

message(STATUS, "HERE")
add_library(libxmlmm SHARED "")
target_link_libraries(libxmlmm LibXml2)
message(STATUS, "HERE")

target_sources("libxmlmm"
    PRIVATE ${libxmlmm_header}
    PRIVATE ${libxmlmm_src}
)


install(TARGETS "libxmlmm" EXPORT ${PROJECT_NAME}Targets DESTINATION ${CMAKE_INSTALL_LIBDIR})
install(
    DIRECTORY "libxmlmm"
    DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/libxmlmm
    FILES_MATCHING PATTERN "*.h")

set(CMAKE_STATIC_LIBRARY_PREFIX "")
set(CMAKE_SHARED_LIBRARY_PREFIX "")
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)

CONFIGURE_FILE(
  "${CMAKE_CURRENT_SOURCE_DIR}/cmake_uninstall.cmake.in"
  "${CMAKE_CURRENT_BINARY_DIR}/cmake_uninstall.cmake"
  IMMEDIATE @ONLY
)

ADD_CUSTOM_TARGET(uninstall
  "${CMAKE_COMMAND}" -P "${CMAKE_CURRENT_BINARY_DIR}/cmake_uninstall.cmake"
)

I get the following output:

michael@michael-B360M-DS3H:~/Documents/dbcppp/build$ make clean; make -j
[ 25%] Building CXX object CMakeFiles/libxmlmm.dir/third-party/libxmlmm/libxmlmm/Attribute.cpp.o
[ 25%] Building CXX object CMakeFiles/libxmlmm.dir/third-party/libxmlmm/libxmlmm/Document.cpp.o
[ 25%] Building CXX object CMakeFiles/libxmlmm.dir/third-party/libxmlmm/libxmlmm/Content.cpp.o
[ 33%] Building CXX object CMakeFiles/libxmlmm.dir/third-party/libxmlmm/libxmlmm/CData.cpp.o
[ 41%] Building CXX object CMakeFiles/libxmlmm.dir/third-party/libxmlmm/libxmlmm/Comment.cpp.o
[ 50%] Building CXX object CMakeFiles/libxmlmm.dir/third-party/libxmlmm/libxmlmm/Element.cpp.o
[ 66%] Building CXX object CMakeFiles/libxmlmm.dir/third-party/libxmlmm/libxmlmm/Node.cpp.o
[ 66%] Building CXX object CMakeFiles/libxmlmm.dir/third-party/libxmlmm/libxmlmm/LibXmlSentry.cpp.o
[ 75%] Building CXX object CMakeFiles/libxmlmm.dir/third-party/libxmlmm/libxmlmm/ProcessingInstruction.cpp.o
[ 83%] Building CXX object CMakeFiles/libxmlmm.dir/third-party/libxmlmm/libxmlmm/Text.cpp.o
[ 91%] Building CXX object CMakeFiles/libxmlmm.dir/third-party/libxmlmm/libxmlmm/utils.cpp.o
[100%] Linking CXX shared library libxmlmm.so
/bin/ld: cannot find -lLibXml2
collect2: error: ld returned 1 exit status
make[2]: *** [CMakeFiles/libxmlmm.dir/build.make:234: libxmlmm.so] Error 1
make[1]: *** [CMakeFiles/Makefile2:104: CMakeFiles/libxmlmm.dir/all] Error 2
make: *** [Makefile:130: all] Error 2

[MichaelBMiner]

I appreciate all of your help. I am having one more issue! I got it to build with my cross compiled library but I am not getting a dbcppp binary or libdbcppp.so file. Can you speculate why? My CMakeLists.txt is as follows:

cmake_minimum_required(VERSION 3.12)
project("libdbcppp" VERSION 0.1.0)

find_package(LibXml2 REQUIRED)
include_directories(${LIBXML2_INCLUDE_DIRS})

message(STATUS, GOT HERE LOL)
message(STATUS, ${LIBXML2_INCLUDE_DIRS})

option(build_tests "Build tests" ON)
option(build_examples "Build examples" ON)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_STATIC_LIBRARY_PREFIX "")
set(CMAKE_SHARED_LIBRARY_PREFIX "")
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)

if (CMAKE_CXX_COMPILER_ID MATCHES "MSVC")
	add_definitions("/bigobj")
endif()

include_directories("include")
include_directories("third-party/libxmlmm/libxmlmm")
include_directories("/mnt/WorkDrive/Documents/EVCC_Application/build-fb/tmp/work/cortexa7t2hf-neon-poky-linux-gnueabi/boost")
include_directories("/mnt/WorkDrive/Documents/EVCC_Application/build-fb/tmp/work/cortexa7t2hf-neon-poky-linux-gnueabi/libxml2/2.9.10-r0/libxml2-2.9.10/include")
include_directories("third-party/cxxopts/include")

file(GLOB libxmlmm_header
    "third-party/libxmlmm/libxmlmm/*.h"
)
file(GLOB libxmlmm_src
    "third-party/libxmlmm/libxmlmm/*.cpp"
)

add_library(libxmlmm SHARED "")
target_link_libraries(libxmlmm ${LIBXML2_LIBRARIES})

target_sources("libxmlmm"
    PRIVATE ${libxmlmm_header}
    PRIVATE ${libxmlmm_src}
)


install(
    TARGETS "libxmlmm" EXPORT ${PROJECT_NAME}Targets
    DESTINATION ${CMAKE_INSTALL_LIBDIR})
install(
    DIRECTORY "libxmlmm"
    DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/libxmlmm
    FILES_MATCHING PATTERN "*.h")

set(CMAKE_STATIC_LIBRARY_PREFIX "")
set(CMAKE_SHARED_LIBRARY_PREFIX "")
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)

CONFIGURE_FILE(
  "${CMAKE_CURRENT_SOURCE_DIR}/cmake_uninstall.cmake.in"
  "${CMAKE_CURRENT_BINARY_DIR}/cmake_uninstall.cmake"
  IMMEDIATE @ONLY
)

ADD_CUSTOM_TARGET(uninstall
  "${CMAKE_COMMAND}" -P "${CMAKE_CURRENT_BINARY_DIR}/cmake_uninstall.cmake"
)

[MichaelBMiner]

I was missing add_subdirectory(src)