I'm new to the world of cmake and linking to libaries. Now for a project I need to include a third party library in the current application. However I'm having problems linking to the library.
Here is what I have:
The library is build in the location D:/qwt-6.1.2, which contains:
the folder /src with the header and source files
the folder /lib which contains (qwt.dll, qwt.ext, qwt.lib, qwtd.dll, qwtd.ext, qwtd.ilk, qwtd.lib and qwtd.pdb.
I have tried to add the following to the cmake file:
add_executable(Demo main.cpp mainwindow.cpp mainwindow.h )
include_directories(D:/qwt-6.1.2/src)
link_directories(D:/qwt-6.1.2/lib)
target_link_libraries(Demo qwt)
The including goes fine since the intellisense of visual studio can the includes that I do, however when I build I get the error:
Error 1 error LNK1104: cannot open file 'qwt.lib'
Does anybody have an idea what I'm doing wrong? I don't care at the moment if it is statically or dynamically linked.
Related
I am trying to link to shared object library (json-c) using cmake. I am a super beginner with cmake, and have tried the solutions in various SO posts to no avail.
I am following the directions laid out here
first step is to build the json-c library, which I did sucesfully.
Second step is linking to it. That's what I am having issues with. After following these instructions, my project directory structure looks like this:
Project Structure (before running make, build directory was empty)
base
|-json-c-master
|-libjson-c.so
|-libjson-c.a
|-json.h
:
:
:
|-CMakeLists.txt
|-Makefile
|-libjson-c.so
|-build
|-CMakeFiles
|-
:
:
|-Makefile.
|-src
|-main.c
|-project1.c
|-project1.h
The contents of my CMakeLists.txt in ~/base/project1/CMakeLists.txt
cmake_minimum_required(VERSION 3.10)
project(project1) set(CMAKE_CXX_STANDARD 14)
set(SOURCES src/main.c src/project1.h src/project1.c )
add_executable(project1 ${SOURCES})
find_package(json-c CONFIG)
target_link_libraries(${PROJECT_NAME} PRIVATE json-c::json-c)
then, I ran
cd build
cmake -DCMAKE_PREFIX_PATH=/home/<username>/base/project1/json-c-master ..
this populated the previously empty build directory.
then, I ran make
and I got the error that in project1.h, which #includes "json.h", the file "json.h" was not found.
How can I link json.h to project1.h?
I again appreciate your patience, I am a super noob with cmake and I've been pouring over their documentation and other SO posts to no avail.
I want to link expernal 'parquet' project ( https://github.com/apache/arrow/tree/master/cpp ) as part of my current project on Linux.
For this purposes I ran cmake of parquet with such parameters
cd build_parquet
cmake -DCMAKE_BUILD_TYPE=Release -DARROW_PARQUET=ON \
-DBoost_NO_BOOST_CMAKE=TRUE -DBoost_NO_SYSTEM_PATHS=TRUE -DBOOST_ROOT=${BOOST_BUILD_DIR}/include -DBOOST_LIBRARYDIR=${BOOST_BUILD_DIR}/lib/boost -DARROW_BOOST_USE_SHARED=OFF -DBOOST_INCLUDEDIR=${BOOST_BUILD_DIR}/include/boost ..
cmake --build . --config Release
// There are a lot of dependencies except boost, but only boost required to be installed on system, since other could be downloaded and installed by cmake script
Project successfully compiled. I got executable which could launch, generated static libs libarrow.a, libparquet.a, shared libraries libarrow.so, libparquet.so
In my main project I want to use such libraries and I use such commands in cmake to find them
find_path(PARQUET_INCLUDE_DIR NAMES arrow/api.h PATHS ${PARQUET_DIR}/src)
find_library(PARQUET_LIBRARY_RELEASE NAMES parquet.a
PATHS build_parquet/release/Release/ )
find_library(ARROW_LIBRARY_RELEASE NAMES arrow.a
PATHS build_parquet/release/Release/ )
set(PARQUET_LIBRARIES_RELEASE ${PARQUET_LIBRARY_RELEASE} ${ARROW_LIBRARY_RELEASE} )
include(FindPackageHandleStandardArgs)
find_package_handle_standard_args(Parquet DEFAULT_MSG PARQUET_INCLUDE_DIR
${PARQUET_LIBRARIES_RELEASE } )
That's work okay, libraries and includes are found.
Then I link this libraries to my project
target_link_libraries(${myExe} ${PARQUET_LIBRARIES_RELEASE} ${mySomeOtherLibraries} )
after this I got enormous amount of linker errors such that
libparquet.a(column_writer.cc.o): In function `apache::thrift::transport::TMemoryBuffer::~TMemoryBuffer()':
column_writer.cc:(.text._ZN6apache6thrift9transport13TMemoryBufferD0Ev[_ZN6apache6thrift9transport13TMemoryBufferD5Ev]+0x3): undefined reference to `vtable for apache::thrift::transport::TMemoryBuffer'
.....
so that's what I don't understand much, why lib compiled well in parquet project itself but has a lot of unresolved now, when I use it to link in my own project? Moreover I compiled project for windows and when I did the same things, but with arrow.lib and parquet.lib (instead of libparquet.a and libarrow.a ) things worked fine! I was needed only to put arrow.dll, parquet.dll to executables to run project. But in Linux I've already crashed my head
So, why it doesn't work, what I should do to finally link the project with library ?
Update
I found the problem, I had to link libraries with adding .so files (not only .a files) like this
find_library(PARQUET_LIBRARY_RELEASE NAMES parquet.so parquet.a
PATHS build_parquet/release/Release/ )
find_library(ARROW_LIBRARY_RELEASE NAMES arrow.so arrow.a
PATHS build_parquet/release/Release/ )
set(PARQUET_LIBRARIES_RELEASE ${PARQUET_LIBRARY_RELEASE} ${ARROW_LIBRARY_RELEASE} )
Project is builded. So now the question is, why I need to add .so files to linker (in Windows only static .lib are enough), is it always a case when I build project in Linux ? Is order of linkage important ( .so files first and .a files next ? )
As Uwe wrote in a comment, the https://github.com/apache/parquet-cpp repository is deprecated, and the Parquet C++ library is being developed as part of the Apache Arrow C++ codebase https://github.com/apache/arrow/tree/master/cpp. Can you try building based on that, and if you have trouble can you post on the dev#arrow.apache.org mailing list?
You have succeed to build the project when link with the shared (.so) libraries instead of the static (.a) ones.
(The command find_library actually looks for one library, which name is listed in NAMES option. In your case it found .so library because its name comes before the .a one).
Actually, both shared and static parquet libraries contain the same set of symbols, and both sets are insufficient for link. The difference is that the shared library contains information, where to find remaining symbols (in the thrift library in your case), but the static library doesn't.
For correctly link with the static libraries, you need to list dependent libraries manually.
On Windows .lib file may mean either a static library, or a import file for the shared (.dll) one. It seems that you link with the dynamic one (it has no lib prefix), which succeed like on Linux.
For one of my Qt Embedded projects I'm using a external Qt lib called SMTPEmail. This lib needs to be compiled before being included into a project, something that I managed to do successfully both for Qt 4.8 ARM and for Desktop.
The problem I'm getting is that when I include the headers into my project and include the library in the .pro, the linker gives me
(path_to_libs)/libSMTPEmail.so: undefined reference to `QSslSocket::connectToHostEncrypted(QString const&, unsigned short, QFlags<QIODevice::OpenModeFlag>)'
(path_to_libs)/libSMTPEmail.so: undefined reference to `QSslSocket::QSslSocket(QObject*)'
collect2: ld returned 1 exit status
make: *** [re8k_interface-tgt] Error 1
but only for compiling for ARM. IOW compiling the lib for both ARM and Desktop goes OK, compiling the project for Desktop using the lib goes OK but compiling it for ARM using the lib goes wrong.
Following this forum thread I suspected this could be due to missing the link to the library file of openssl (the project points to different lib folders when compiling for different environments). So I searched for all "openssl" related files inside the compiler for ARM (arm-arago-linux-gnueabi) and included in the same folder where the .so is located; same error. I then suspected the lib itself had other dependencies which were not in the path_to_libs, so I did a readelf -d libSMTPEmail.so and later in the .so.1 and readelf did return some lib dependencies that were not inside the same folder of the library. I then copied all such dependencies to the folder and got no success either.
So what could be happening? All dependencies known by me were put in place and I still get the error only for the situation where the lib is included by another project compiled for ARM.
You need to point your QMake where your libs and header file is in your .pro file;
So find where your library is assume /usr/local/include then ;
INCLUDEPATH += /usr/local/include
Add which libs you will use;
LIBS += -lSMTPEmail
You can check my answer here;
Two things stand out for me in your question:
1.
undefined reference to
This error message means that there was an error in the linking step of compilation. This occurs when you include a header to a function/class/variable but don't have the definition included in your own sources, or you do not link in a static library that does.
Searching for dependencies in libraries that are already compiled (.dll or .so) is too late, the compiler is looking for a static link, not a dynamic link.
2.
compiling the lib for both ARM and Desktop goes OK, compiling the
project for Desktop using the lib goes OK but compiling it for ARM
using the lib goes wrong.
This suggests that you are using conditional compilation in your .pro file that does a "both" compilation, a "desktop only" compilation and a "ARM only" compilation. If this is correct, you need to examine your compilation instructions for your "ARM only" compilation.
The error message itself refers to you using two functions from the QSslStock class. These are part of the QtNetwork module so you should have the following in your .pro file in order for the necessary links to be formed.
Qt += network
I was wondering how do I include libyuv library to my Android Studio Project. I have the "libyuv_static.a" file which is a pre-compiled binary file but I did everything to include it in my project. I created a folder inside src/main named jniLibs and puted the binary file inside the folder but in runtime it doesn't load the library and it gives me this:
Caused by: java.lang.UnsatisfiedLinkError: Couldn't load libyuv2rgb
from loader
dalvik.system.PathClassLoader[dexPath=/data/app/com.example.myproject-1.apk,libraryPath=/data/app-lib/com.example.myproject-1]:
findLibrary returned null
. Could someone please share his/her experience.
In order to include a native library into an Android project, you have to get a .so file (shared library), not a .a (static library).
ie. you should end up with src/main/jniLibs/<abi>/libyuv_shared.so with <abi> being armeabi, armeabi-v7a, arm64-v8a, x86, x86_64, mips, mips64 (any architecture your app and lib support).
There is an Android package now: https://github.com/crow-misia/libyuv-android, installable from mavenCentral:
dependencies {
implementation 'io.github.crow-misia.libyuv:libyuv-android:0.25.0'
}
For usage see https://github.com/crow-misia/libyuv-android/blob/main/sample/src/main/java/app/MainActivity.kt
I have a CMake module to locate FreeGLUT:
FIND_PATH(FREEGLUT_INCLUDE_DIR NAMES GL/freeglut.h)
FIND_LIBRARY(FREEGLUT_LIBRARY NAMES freeglut freeglut_static)
SET(FREEGLUT_LIBRARIES ${FREEGLUT_LIBRARY})
SET(FREEGLUT_INCLUDE_DIRS ${FREEGLUT_INCLUDE_DIR})
INCLUDE(FindPackageHandleStandardArgs)
FIND_PACKAGE_HANDLE_STANDARD_ARGS(FreeGLUT DEFAULT_MSG FREEGLUT_LIBRARY FREEGLUT_INCLUDE_DIR)
MARK_AS_ADVANCED(FREEGLUT_INCLUDE_DIR FREEGLUT_LIBRARY)
It works fine and locates freeglut_static.lib when I generate NMake Makefiles on Windows. I'm attempting to statically link FreeGLUT into my DLL:
FIND_PACKAGE(FreeGLUT REQUIRED)
ADD_LIBRARY(vti SHARED ${VTI_SOURCES})
ADD_DEFINITIONS("-DBUILD_VTI=1 -DFREEGLUT_STATIC=1")
INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR}/include ${FREEGLUT_INCLUDE_DIRS})
TARGET_LINK_LIBRARIES(vti ${FREEGLUT_LIBRARIES})
My source code builds correctly, but when it gets to the linking stage, VC++ fails with:
LINK : fatal error LNK1104: cannot open file 'freeglut.lib'
Which is strange since freeglut.lib isn't mentioned anywhere that I can see in the generated NMake makefiles. It should be trying to link with freeglut_static.lib, which CMake locates and sets in FREEGLUT_LIBRARIES.
What might be causing this?
This is caused with pragma directives in FreeGLUT code (see freeglut_std.h). Using FREEGLUT_STATIC should really fix that for you, but I think you should pass it to CMake without quotes: ADD_DEFINITIONS(-DBUILD_VTI -DFREEGLUT_STATIC)