Compiling error: "cannot find -lQtCore4" - c++

Yesterday I downloaded the Qt4 Opensource library for linux. After running
./configure
./make
./make install
And inserting this into my .bashrc-file:
PATH=/usr/local/TrollTech/Qt-4.7.3/bin:$PATH
export PATH
After this, I ran cmake in order to produce a Makefile for me. CMakeLists.txt:
project(VTKToVTFx)
cmake_minimum_required(VERSION 2.6)
find_package(VTK REQUIRED)
find_package(Qt4 REQUIRED)
include(${VTK_USE_FILE})
include(${QT_USE_FILE})
SET(VTK_TO_VTFX_FORMS main.ui)
QT4_WRAP_UI(VTK_TO_VTFX_FORMS_UIC ${VTK_TO_VTFX_FORMS})
SET(MOC_HEADERS VTKToVTFx.h)
qt4_wrap_cpp(MOC_OUTFILES ${MOC_HEADERS})
SET(CPP_SOURCES VTKToVTFx.cpp
VTKPatch.cpp
VTKFile.cpp
VTKData.cpp
VTKDataHolder.cpp
)
add_executable(VTKToVTFx ${CPP_SOURCES} ${VTK_TO_VTFX_FORMS_UIC} ${MOC_OUTFILES})
# Adds folders for Visual Studio solution explorer (and for Xcode explorer)
source_group( "Generated" FILES ${MOC_FILES_CPP} ${VTK_TO_VTFX_FORMS_UIC} ${QRC_FILES_CPP} ${MOC_OUTFILES})
INCLUDE_DIRECTORIES(${CMAKE_CURRENT_BINARY_DIR})
target_link_libraries(VTKToVTFx vtkHybrid)
target_link_libraries(VTKToVTFx QtCore4)
target_link_libraries(VTKToVTFx QtGUI4)
This CMakeLists.txt works perfectly well on Windows, but when I try to compile the output on my installation of Ubuntu, this error occurs:
/usr/bin/ld: cannot find -lQtCore4
/usr/bin/ld: cannot find -lQtGUI4
Anyone who could point me to my problem here?

In the unix[like] world, the slash is the path seperator, not the backslash.
\usr\local\TrollTech\Qt-4.7.3\bin evaluates to usrlocalTrollTechQt-4.7.3bin.
edit: Also, your CMakeLists.txt seems a bit foul. Have a look at http://qtnode.net/wiki/Qt4_with_cmake . Instead of
target_link_libraries(VTKToVTFx QtCore4)
use something like (source is the linked site):
To add support for Qt4 libraries like network or qttest, you need to add both the include files and corresponding libraries. For example, to add support for the network and qttest libraries, you can use:
INCLUDE_DIRECTORIES(
${QT_INCLUDE_DIR}
${QT_QTNETWORK_INCLUDE_DIR}
${QT_QTTEST_INCLUDE_DIR}
)
TARGET_LINK_LIBRARIES(
${QT_LIBRARIES}
${QT_QTNETWORK_LIBRARIES}
${QT_QTTEST_LIBRARIES}
)
Even within the 4.x line of releases, libraries have been renamed and will be renamed. Fortunately there is no need for hardcodery :)

Related

CLion Not Finding GLUT with CMake

I have a problem that I can't seem to find the settings to modify.
When attempting to find the GLUT package using CLion's CMake utilities on Ubuntu, it does not find GLUT. Using command-line CMake and Makefile commands, however, finds the dependencies perfectly and allows the following to generate and compile:
# CMakeLists.txt
cmake_minimum_required(VERSION 3.16)
project(mre)
set(CMAKE_CXX_STANDARD 20)
find_package(OpenGL REQUIRED) # Works in CLion and terminal
find_package(GLUT REQUIRED) # Works only in terminal
include_directories(GL)
add_executable(mre mre.cpp)
target_link_libraries(mre -lglut -lGLU -lGL)
// mre.cpp
#include <GL/gl.h>
#include <GL/glut.h>
int main()
{
return 0;
}
Whereas attempting to use these files in a CLion project would cause errors (first unable to find GLUT, mitigated by manually setting library and include variables; then GL/glut.h: No such file or directory, which I am unable to fix).
Does anyone have any suggestions? I'm assuming it's something to do with a working directory or prefixes, but CMAKE_PREFIX_PATH is unset in CLion, and setting it to various values does nothing to solve the problem.
Thanks!
You know something has gone wrong when you write include_directories or -l flags by hand. You should absolutely always link to libraries via their imported targets.
See the documentation:
OpenGL package: https://cmake.org/cmake/help/latest/module/FindOpenGL.html
GLUT package: https://cmake.org/cmake/help/latest/module/FindGLUT.html
Try this revision:
cmake_minimum_required(VERSION 3.16)
project(mre)
find_package(OpenGL REQUIRED)
find_package(GLUT REQUIRED)
add_executable(mre mre.cpp)
target_link_libraries(mre PRIVATE OpenGL::GL OpenGL::GLU GLUT::GLUT)
target_compile_features(mre PRIVATE cxx_std_20)
As for not being able to find GLUT... just set CMAKE_PREFIX_PATH in CLion's settings to whichever directory on your system contains include/GL/glut.h.
Alternative solution
CLion was installed through the Software Center via Flatpak, which uses some kind of filesystem sandboxing that may be interfering with paths. I tried explicitly allowing /usr and related paths, but had no effect.
I have reinstalled via JetBrains's official archive, which correctly detects GLUT and OpenGL. Their official snap also works properly.

How resolve the error find_package not providing in CMake [duplicate]

I wrote a CMakeLists.txt for a project in C++, which uses OpenCV libraries. When I try to create the project using cmake, I get the next configuration problem:
CMake Error at CMakeLists.txt:15 (find_package):
Could not find module FindOpenCV.cmake or a configuration file for package
OpenCV.
Adjust CMAKE_MODULE_PATH to find FindOpenCV.cmake or set OpenCV_DIR to the
directory containing a CMake configuration file for OpenCV. The file will
have one of the following names:
OpenCVConfig.cmake
opencv-config.cmake
The fact is that I have an environment variable for the path which I use in Visual Studio with no problems. If I don't include OpenCV, then I can configure and generate with no problem, but I need to solve the problem. I don't understand why cmake cannot find the OpenCV path or how to fix it.
I also used the recommendations mentioned in this link:
FindOpenCV.cmake
Does anybody had this problem too?
The error you're seeing is that CMake cannot find a FindOpenCV.cmake file, because cmake doesn't include one out of the box. Therefore you need to find one and put it where cmake can find it:
You can find a good start here. If you're feeling adventurous you can also write your own.
Then add it somewhere in your project and adjust CMAKE_MODULE_PATH so that cmake can find it.
e.g., if you have
CMakeLists.txt
cmake-modules/FindOpenCV.cmake
Then you should do a
set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CMAKE_CURRENT_SOURCE_DIR}/cmake-modules)
In your CMakeLists.txt file before you do a find_package(OpenCV)
If you are on Linux, you just need to fill the OpenCV_DIR variable with the path of opencv (containing the OpenCVConfig.cmake file)
export OpenCV_DIR=<path_of_opencv>
apt-get install libopencv-dev
export OpenCV_DIR=/usr/share/OpenCV
the header of cpp file should contain:
#include
#include "opencv2/highgui/highgui.hpp"
#include
#include
not original cv.h
find / -name "OpenCVConfig.cmake"
export OpenCV_DIR=/path/found/above
I had this exact same problem. I fixed it by adding the following line to my FindOpenCV.cmake file. Put it anywhere at the top before the rest of the code.
set (OpenCV_DIR /home/cmake/opencv/compiled) #change the path to match your complied directory of opencv
Basically you are telling FindOpenCV.cmake where to find opencv files assuming the other compilation can find the FindOpenCV.cmake
I faced the same error. In my case this "OpenCVConfig.cmake" file is located in /usr/local/share/OpenCV. In CMakeLists.txt add the line
set(OpenCV_DIR /usr/local/share/OpenCV)
as suggested by the error message.
if you are on windows, you can add opencv path to OpenCV_DIR yourself.
(OpenCV_DIR is in the red region)
the path is like "D:/opencv244/build".
you can find file "OpenCVConfig.cmake" under the path.
Another possibility is to denote where you can find OpenCV_DIR in the CMakeLists.txt file. For example, the following cmake scripts work for me:
cmake_minimum_required(VERSION 2.8)
project(performance_test)
set(OpenCV_STATIC ON)
set(OpenCV_CUDA OFF)
set(OpenCV_DIR "${CMAKE_SOURCE_DIR}/../install")
find_package(OpenCV REQUIRED)
include_directories(${OpenCV_INCLUDE_DIRS})
link_directories(${OpenCV_LIB_DIR})
file(GLOB my_source_files ./src/*)
add_executable( performance_test ${my_source_files})
target_link_libraries(performance_test ${OpenCV_LIBS})
Just to remind that you should set OpenCV_STATIC and OpenCV_CUDA as well before you invoke OpenCVConfig.cmake. In my case the built library is static library that does not use CUDA.
On my Fedora machine, when I typed "make" I got an error saying it could not find "cv.h". I fixed this by modifying my "OpenCVConfig.cmake" file.
Before:
SET(OpenCV_INCLUDE_DIRS "${OpenCV_INSTALL_PATH}/include/opencv;${OpenCV_INSTALL_PATH}/include")
SET(OpenCV_LIB_DIR "${OpenCV_INSTALL_PATH}/lib64")
After:
SET(OpenCV_INCLUDE_DIRS "/usr/include/opencv;/usr/include/opencv2")
SET(OpenCV_LIB_DIR "/usr/lib64")
I am using Windows and get the same error message. I find another problem which is relevant.
I defined OpenCV_DIR in my path at the end of the line. However when I typed "path" in the command line, my OpenCV_DIR was not shown. I found because Windows probably has a limit on how long the path can be, it cut my OpenCV_DIR to be only part of what I defined. So I removed some other part of the path, now it works.
I had the same error, I use windows. I add "C:\opencv\build" (opencv folder) to path at the control pannel.
So, That's Ok!!
For me (on Ubuntu), I just run:
sudo apt-get install libopencv-dev
Followed #hugh-pearse 's and #leszek-hanusz 's answers, with a little tweak. I had installed opencv from ubuntu 12.10 repository (libopencv-)* and had the same problem. Couldn't solve it with export OpenCV_DIR=/usr/share/OpenCV/ (since my OpenCVConfig.cmake whas there). It was solved when I also changed some lines on the OpenCVConfig.cmake file:
# ======================================================
# Include directories to add to the user project:
# ======================================================
# Provide the include directories to the caller
#SET(OpenCV_INCLUDE_DIRS "${OpenCV_INSTALL_PATH}/include/opencv;${OpenCV_INSTALL_PATH}/include")
SET(OpenCV_INCLUDE_DIRS "/usr/include/opencv;/usr/include/opencv2")
INCLUDE_DIRECTORIES(${OpenCV_INCLUDE_DIRS})
# ======================================================
# Link directories to add to the user project:
# ======================================================
# Provide the libs directory anyway, it may be needed in some cases.
#SET(OpenCV_LIB_DIR "${OpenCV_INSTALL_PATH}/lib")
SET(OpenCV_LIB_DIR "/usr/lib")
LINK_DIRECTORIES(${OpenCV_LIB_DIR})
And that worked on my Ubuntu 12.10. Remember to add the target_link_libraries(yourprojectname ${OpenCV_LIBS}) in your CMakeLists.txt.
When you install the libraries in the c drive (windows). the CMakeLists.txt shoud be looking like below:
cmake_minimum_required(VERSION 3.0.0)
project(test_opencv VERSION 0.1.0)
include(CTest)
enable_testing()
find_package(OpenCV REQUIRED)
include_directories(${OpenCV_INCLUDE_DIRS})
add_executable(test_opencv main.cpp)
target_link_libraries(test_opencv ${OPENCV_LIBS})
set(CPACK_PROJECT_NAME ${PROJECT_NAME})
set(CPACK_PROJECT_VERSION ${PROJECT_VERSION})
include(CPack)
finding the package and include directories
when building the project in VS code. Run the visual studio code with admin rights as the OpenCV is installed inside C drive.

CMake BUILD undefined reference (findpng)

I'm still very new to CMake so feedback is definitely welcome. So, I'm trying to build a simple application that should eventually create a pdf using the library libharu.
I think i figured it out how to link the library. But I still receive build errors for the findpng module (I suppose libharu depends on it)
CMakeLists.txt:
cmake_minimum_required(VERSION 3.2.0 FATAL_ERROR) # current latest stable version (if lower give FATAL_ERROR)
project(pdf_generator VERSION 0.1.0) # name of the project, version.
file(GLOB TARGET_SRC "./src/*.cpp") # Creates variable, using globbing.
include_directories(${PROJECT_SOURCE_DIR}/include) # list of directories to be used as header search paths.
add_executable(main ${TARGET_SRC}) # Create an executable of set of source files [exe name files to bundle].
find_library(libhpdf_location NAMES libhpdf.a) # find the location of libhpdf.a and save the value in the variable libhpdf_location.
message(STATUS ${libhpdf_location}) # print status of variable.
add_library(libhpdf STATIC IMPORTED) # Add library via a static import.
set_target_properties(
libhpdf PROPERTIES
IMPORTED_LOCATION ${libhpdf_location}
)
target_link_libraries(main libhpdf)
I've never worked with that particular library before, but skimming their CMakeLists.txt on GitHub it seems like libharu has optional dependencies on libpdf and zlib. Without knowing how you built your version of libharu I'm going to assume that both are needed.
Luckily, CMake comes with find-modules for both libpng and zlib, so adding the following should work:
find_package(PNG REQUIRED)
find_package(ZLIB REQUIRED)
set_target_properties(libhpdf
PROPERTIES
INTERFACE_LINK_LIBRARIES "ZLIB::ZLIB;PNG::PNG"
)
Looks like all you need to do is tell cmake to link libpng.

Using SDL2 with CMake in CLion

After hours of scouring the web and SO for a solution I'm at a standstill. Nothing has worked so far for me...
I'm on Windows, using CLion IDE which uses CMake. My goal is to correctly link SDL2 to my project and use it through #include "SDL.h" which is the correct way.
The format of my CMakeLists.txt file
Specifics regarding the directory where I should have put the MingW development library of SDL2
Any requirements regarding windows ENV variables that I might have to set.
My CMakeLists.txt looks like this:
cmake_minimum_required(VERSION 3.6)
project(sdl2Project)
set(CMAKE_CXX_STANDARD 11)
#This is where sdl2-config.cmake is located
set(CMAKE_PREFIX_PATH ${CMAKE_PREFIX_PATH} "C:/Users/MyUserName/CLibraries/SDL2-2.0.5/x86_64-w64-mingw32/lib/cmake/SDL2")
set(SOURCE_FILES main.cpp)
add_executable(sdl2Project ${SOURCE_FILES})
find_package(sdl2 REQUIRED)
target_include_directories(sdl2Project PUBLIC ${SDL2_INCLUDE_DIRS})
target_link_libraries(sdl2Project ${SDL2_LIBRARIES})
There is no FindSDL2.cmake file used.
The SDL2 library I downloaded from libsdl.org is located in:
C:/Users/MyUserName/CLibraries/SDL2-2.0.5/x86_64-w64-mingw32
I have no experience with CMake so I'm unable to truly understand where the problem stems from. What are the steps I need to take in order for it to find the library and link it correctly??
EDIT:
My Project structure is the following:
sdl2Project
cmake-build-debug
CMakeLists.txt
main.cpp
Looking in your FindSDL2.cmake, you need to provide an hint to CMake about where the library is installed. You could do this by setting an environment variable SDLDIR, but you shouldn't. General advice: you shouldn't use a CMake package that wasn't provided with the sources you're using.
Looking in sources of SDL2, root directory contains a file sdl2-config.cmake.in that should have been configured and installed in your install directory as sdl2-config.cmake: that's the package file you should use.
Am I right guessing the file C:/Users/MyUserName/CLibraries/SDL2-2.0.5/sdl2-config.cmake exists?
If yes, to allow CMake to find it, add your install directory to CMAKE_PREFIX_PATH, before calling find_package:
set(CMAKE_PREFIX_PATH
${CMAKE_PREFIX_PATH}
"C:/Users/MyUserName/CLibraries/SDL2-2.0.5"
)
find_package(sdl2 REQUIRED)
Note the use of "/" in the path instead of "\" which could be interpreted as escaping character. Quotes around the path are only necessary if the path contains whitespaces.
EDIT:
Moreover, you misused target_link_libraries with a wrong target: SDL2 which you don't build in your project, instead of sdl2Project.
You also used a wrong variable: SDL2_LIBRARY instead of SDL2_LIBRARIES; you can see the good variable name by looking in sdl2-config.cmake.
You may consider target_include_directories instead of include_directories, but again the variable name you used is wrong: SDL2_INCLUDE_DIR instead of SDL2_INCLUDE_DIRS.
Try:
target_include_directories(sdl2Project PUBLIC ${SDL2_INCLUDE_DIRS})
target_link_libraries(sdl2Project ${SDL2_LIBRARIES})

Qt w/ Cmake: set(QT_USE_QTWEBKIT TRUE) not working

I'm attempting to build a Qt-based application using cmake (It's what Kdevelop gave me). I tried to use a QWebView;
QWebView *webView = new QWebView( this );
webView->load(QUrl("http://google.ca"));
But it failed with Undefined Reference errors...
undefined reference to `QWebView::QWebView(QWidget*)'
undefined reference to `QWebView::load(QUrl const&)'
I looked it up and I needed to add QTWEBKIT to my project, but all the solutions said to add it to my .pro file... And I'm not using .pro. In the QT documentation it said to add "set(QT_USE_QTWEBKIT TRUE)" to my CMAKE file, this is my CMakeLists.txt file now:
#-------------------------------------------------------------------------------
# Corrections Tool CMAKE list
#-------------------------------------------------------------------------------
project(corrections)
# Versioning Requirements
#-------------------------------------------------------------------------------
cmake_minimum_required(VERSION 2.6)
find_package(Qt4 REQUIRED)
# Include QT Librtaries
#-------------------------------------------------------------------------------
set(QT_USE_QTWEBKIT TRUE)
# Set Sources
#-------------------------------------------------------------------------------
set(corrections_SRCS corrections.cpp main.cpp utilities.cpp prettySplash.cpp)
#The Rest
#-------------------------------------------------------------------------------
include_directories(${QT_INCLUDES} ${CMAKE_CURRENT_BINARY_DIR})
qt4_automoc(${corrections_SRCS})
add_executable(corrections ${corrections_SRCS})
target_link_libraries(corrections ${QT_QTCORE_LIBRARY} ${QT_QTGUI_LIBRARY})
install(TARGETS corrections RUNTIME DESTINATION bin)
But I'm still getting the errors, so either I did it wrong, in the wrong place, etc. I've also cleaned out and reconfigured my project several times making sure I wasn't using a bad generated makefile.
How would I either fix my cmake config to actually work, or convert my project to using .pro (with minimum stress & heartache)?
Thank you.
The canonical way to select Qt components in CMake is to specify the them in the find_package call and then to include ${QT_USE_FILE}
FIND_PACKAGE( Qt4 COMPONENTS QtWebKit REQUIRED )
INCLUDE( ${QT_USE_FILE} )
...
TARGET_LINK_LIBRARIES( corrections ${QT_LIBRARIES} )
This already configures the include directories and sets ${QT_LIBRARIES} to contain all relevant Qt libraries (i.e. your selected component and all Qt libraries it depends on).
So you don't need to manually add the libraries by listing them individually as you did in your example.
Edit:
Additional explaination:
The COMPONENTparameter to FIND_PACKAGE actually does the same as your manual call to set QT_USE_WEBKIT. But this variable is only evaluated/used in UseQt4.cmake which is included (and "executed") by the INCLUDEcommand. See CMake documentation of FindQt4 for details.
You do not appear to be linking against all of the Qt libraries. Use ${QT_LIBRARIES} instead of ${QT_QTCORE_LIBRARY} ${QT_QTGUI_LIBRARY} in your target_link_libraries
target_link_libraries(corrections ${QT_LIBRARIES} )