I"m linking SDL with my application using cmake (winxp sp3, cmake 2.8.4).
cmake_minimum_required(VERSION 2.8)
find_package(SDL REQUIRED)
set(src WIN32 main.cpp)
include_directories(${QT_INCLUDE_DIR} ${QT_QTGUI_INCLUDE_DIR} ${SDL_INCLUDE_DIR})
add_executable(test ${src})
target_link_libraries(test ${SDL_LIBRARY})
Problem: SDL_LIBRARY contains SDLmain.lib, and I need to avoid linking with it (I already have one other library that contains main but isn't mentioned in this cmakelists.txt example).
I need to remove SDLmain entry from SDL_LIBRARY. This must be done without using hard-coded paths to the library - basically I need to keep using find_package to set up sdl-related variables, but I must ensure that SDLmain is not within SDL_LIBRARY. Also, I'm using cmake 2.8.4 which doesn't have string(FIND).
How can I do that?
Does that help?
FindSDL.cmake:
# This module responds to the the flag:
# SDL_BUILDING_LIBRARY
# If this is defined, then no SDL_main will be linked in because
# only applications need main().
# Otherwise, it is assumed you are building an application and this
# module will attempt to locate and set the the proper link flags
# as part of the returned SDL_LIBRARY variable.
Related
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.
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.
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})
In Qt Creator (version 3.0.1, with Qt version 5.2.1), I have made a custom cmake step (instead of qmake), with the following CMakeLists.txt file:
cmake_minimum_required (VERSION 2.8)
add_executable (myapp source.cpp)
target_link_libraries(myapp dl)
In my source.cpp file, I have the following code:
#include <dlfcn.h>
int main()
{
dlopen("mylibrary.so", RTLD_NOW|RTLD_GLOBAL);
return 0;
}
And mylibrary.so is located in /usr/lib.
When I compile this using cmake and make from the command line, it compiles as expected. However, if I try to build this in Qt Creator, I receive the following error:
undefined reference to `dlopen'
This suggests that Qt Creator does not know where to look to find libdl.so, which is in /usr/lib/x86_64-linux-gnu.
So my question is: Why does running cmake and make from the command line work, whereas building in Qt Creator does not work? And how do I tell Qt Creator where to search for libdl.so?
First of all, you should use QLibrary in Qt software for dealing with dynamic loading, lookup and the like. You would also spare the hassle that you are seeing now.
Secondly, you can use this, but it is a bit hard-wiring things, admittedly:
target_link_libraries(myapp /usr/lib/x86_64-linux-gnu/libdl.so)
Thirdly, the even better approach would be to use some find module for this as follows:
# - Find libdl
# Find the native LIBDL includes and library
#
# LIBDL_INCLUDE_DIR - where to find dlfcn.h, etc.
# LIBDL_LIBRARIES - List of libraries when using libdl.
# LIBDL_FOUND - True if libdl found.
IF (LIBDL_INCLUDE_DIR)
# Already in cache, be silent
SET(LIBDL_FIND_QUIETLY TRUE)
ENDIF (LIBDL_INCLUDE_DIR)
FIND_PATH(LIBDL_INCLUDE_DIR dlfcn.h)
SET(LIBDL_NAMES dl libdl ltdl libltdl)
FIND_LIBRARY(LIBDL_LIBRARY NAMES ${LIBDL_NAMES} )
# handle the QUIETLY and REQUIRED arguments and set LIBDL_FOUND to TRUE if
# all listed variables are TRUE
INCLUDE(FindPackageHandleStandardArgs)
FIND_PACKAGE_HANDLE_STANDARD_ARGS(LibDL DEFAULT_MSG LIBDL_LIBRARY LIBDL_INCLUDE_DIR)
IF(LIBDL_FOUND)
SET( LIBDL_LIBRARIES ${LIBDL_LIBRARY} )
ELSE(LIBDL_FOUND)
SET( LIBDL_LIBRARIES )
ENDIF(LIBDL_FOUND)
MARK_AS_ADVANCED( LIBDL_LIBRARY LIBDL_INCLUDE_DIR )
and then you can find it as follows given that you have it in your cmake module path:
find_package(LIBDL REQUIRED)
I'm attempting to build a Qt-based application using cmake (It's what Kdevelop gave me). I tried to use a QWebView;
QWebView *webView = new QWebView( this );
webView->load(QUrl("http://google.ca"));
But it failed with Undefined Reference errors...
undefined reference to `QWebView::QWebView(QWidget*)'
undefined reference to `QWebView::load(QUrl const&)'
I looked it up and I needed to add QTWEBKIT to my project, but all the solutions said to add it to my .pro file... And I'm not using .pro. In the QT documentation it said to add "set(QT_USE_QTWEBKIT TRUE)" to my CMAKE file, this is my CMakeLists.txt file now:
#-------------------------------------------------------------------------------
# Corrections Tool CMAKE list
#-------------------------------------------------------------------------------
project(corrections)
# Versioning Requirements
#-------------------------------------------------------------------------------
cmake_minimum_required(VERSION 2.6)
find_package(Qt4 REQUIRED)
# Include QT Librtaries
#-------------------------------------------------------------------------------
set(QT_USE_QTWEBKIT TRUE)
# Set Sources
#-------------------------------------------------------------------------------
set(corrections_SRCS corrections.cpp main.cpp utilities.cpp prettySplash.cpp)
#The Rest
#-------------------------------------------------------------------------------
include_directories(${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} )