I'm currently changing one of my projects to cmake for portably. Within the project directory I have a folder with an external library called "boclib", which is build by a regular makefile. I need to link my executable to "ProjectDir"/boclib/bin/libboc.a . My current attempt looks like this:
FIND_LIBRARY(BOCLIB boc ${PROJECT_BINARY_DIR}/boclib/bin)
Message(${BOCLIB})
TARGET_LINK_LIBRARIES(prod ${BOCLIB})
The Meassage output yields the correct library:
"AbsulutePathToProjectDir"/boclib/bin/libboc.a
Which outputs this, when linking:
g++ -lm -ldl CMakeFiles/prod.dir/src/BocData.cpp.o CMakeFiles/prod.dir/src/delay.cpp.o CMakeFiles/prod.dir/src/leoni.cpp.o CMakeFiles/prod.dir/src/main.cpp.o CMakeFiles/prod.dir/src/scope.cpp.o CMakeFiles/prod.dir/src/SerialCom.cpp.o CMakeFiles/prod.dir/src/tester.cpp.o CMakeFiles/prod.dir/src/Utils.cpp.o -o prod boclib/bin/libboc.a -lboost_program_options -lboost_system -lboost_filesystem -lboost_serialization -lboc
There is no -L option for the boclib.
What am I doing wrong?
Any help will be appreciated.
It seems there's two occurence of "boc" library in the g++ command you pasted, the first: boclib/bin/libboc.a that should comes from your target_link_libraries call and a second one: -lboc that must come from something else in your CMakeLists.txt.
You don't need that second one, if you find why it's added and remove it, it should be ok.
Related
I use QtCreator 4.15.2, clang 12.0.1.
I have "generic project" with makefile. File src/test/main.cpp contains import test.StringUtil;. QtCreator complains that module is not found. (Project builds ok, but makefile uses gcc; I'm not familiar with clang.) I tried this:
Generated .pcm file in separate directory:
clang++ -std=c++20 -fmodules --precompile -x c++-module src/test/StringUtil.cpp -o target/clang/test.StringUtil.pcm
Edited myproject.cxxflags in project root so it contains:
-std=c++20 -fmodules -fprebuilt-module-path=/home/me/myproject/target/clang -Wall -Wextra -Wpedantic -fno-rtti
If I specify relative path -fprebuilt-module-path=target/clang then nothing changes; QtCreator still says that module not found. But with absolute path looks like ClangCodeModel gets disabled (crashes?): <No Symbols> in QtCreator's symbols combobox, no syntax errors reporting.
I also tried to compile in additiion to generating .pcm file, with no difference:
clang++ -std=c++20 -fmodules -c -x c++-module src/test/StringUtil.cpp -o target/build/clang/test.StringUtil.o
So: how do I make it work?
When I added support for modules in my own build system I found it easiest to specify each imported module with the flag -fmodule-file="path/to/other.pcm".
In the future I guess that the big build systems will do this aswell. since you need to preprocess the files anyway there is no extra cost. (It could be some extra work if you write your makefiles by hand though)
I don't think that qtcreators code model supports modules as of yet. I have tried but it does not work for me.
I have a sqlite extension file. The source is sqliteext/csv.c. When I build the lib with clang the output file is created at lib/csv.so.
cc -g -fPIC -I /usr/local/include -shared sqliteext/csv.c -o lib/csv.so
When I compile the lib using zig...
zig build-lib -I /usr/local/include -I /usr/include -I /usr/include/x86_64-linux-gnu --c-source sqliteext/csv.c -dynamic --output-dir lib
There are two problems.
zig prefixes the filename with a lib
zig add a version number thing in the suffix
so the output file is lib/libcsv.so.0.0.0
And what's interesting about this is that I need to change the filename in my extension loader (that's ok) but that I also need a symlink to handle the 0.0.0.
I'm still looking at the CLI help but I'm still not seeing the thing I need.
See https://github.com/ziglang/zig/issues/2230 and https://github.com/ziglang/zig/issues/2231
The former was fixed the same day as your post via https://github.com/ziglang/zig/pull/6315
I am trying to build the OpenCV samples which come with the source package and I get the following:
CMake Error at CMakeLists.txt:10 (ocv_check_dependencies):
Unknown CMake command "ocv_check_dependencies".
I did install OpenCV using
cmake .
make
sudo make install
and I got a tutorial snippet working (thus I suppose it is installed correctly as a library). However, compiling the samples does not work.
I guess I have to somehow configure CMake to have “ocv_check_dependencies” - but how? I am lost!
Actually for OpenCV 2.4.4 beta the root CMakeList.txt file says:
OCV_OPTION(BUILD_EXAMPLES "Build all examples"
-DBUILD_EXAMPLES=ON worked just fine for me.
I got it.
In order to build the samples one has to change the default configuration for cmake by providing it via -D. What I did wrong was that I tried to execute cmake from within the samples directory.
The proper way to build the samples is invoking cmake like so (from within the root directory of the unpacked archive):
cmake -DBUILD_SAMPLES .
which will turn samples ON. One can proceed using make, make install than. The samples can be found in bin after building.
See also FAQ
How to compile OpenCV sample code ?
# For OpenCV 3
cd /path/to/opencv/samples/cpp/
#Compile
g++ -ggdb `pkg-config --cflags --libs opencv` facedetect.cpp -o facedetect
#run
./facedetect
Works for me.
googled from this link
mydragonisland's build instructions almost worked for me; with a minor reordering and including accents:
g++ facedetect.cpp -o facedetect `pkg-config --libs opencv`
The macro 'ocv_check_dependencies' is defined in: your_path_to/opencv/cmake/OpenCVModule.cmake
# ensures that all passed modules are available
# sets OCV_DEPENDENCIES_FOUND variable to TRUE/FALSE
macro(ocv_check_dependencies)
set(OCV_DEPENDENCIES_FOUND TRUE)
foreach(d ${ARGN})
if(d MATCHES "^opencv_[^ ]+$" AND NOT HAVE_${d})
set(OCV_DEPENDENCIES_FOUND FALSE)
break()
endif()
endforeach()
endmacro()
The top level CMakeLists.txt contains 'include' commands for files from opencv/cmake/ . Which is why the macro is available when you compile by calling cmake from the root of the opencv sources.
Reason
error message context:
CMake Error at CMakeLists.txt:10 (ocv_check_dependencies):
Unknown CMake command "ocv_check_dependencies".
This error message happens because cmake can't find the definition of ocv_check_dependencies
That's why the console said Unknown CMake command
Solution
If cmake cannot find where ocv_check_dependencies is defined
Just like #Nick Hockings Said:
ocv_check_dependencies is a macro defined in Your/OpenCV/path/OpenCVModule.cmake
macro(ocv_check_dependencies)
set(OCV_DEPENDENCIES_FOUND TRUE)
foreach(d ${ARGN})
if(d MATCHES "^opencv_[^ ]+$" AND NOT HAVE_${d})
set(OCV_DEPENDENCIES_FOUND FALSE)
break()
endif()
endforeach()
endmacro()
The fastest way is to copy this snippet above to your CMakeList.txt file right above where ocv_check_dependencies is
Therefore, cmake can finally understand what it is
That should do the trick, i hope no one else will bother with this question in the future
I got similar errors. My approach is as following:
1) cd xxx/samples 2) mkdir build 3) cd build 4) cmake .. 5) make
Now it works. We could not build individual project under their source files.
Following steps works for me.
Export toolchain path.
cd opencv-3.3.0/samples
cross_cmake &&
cross_make
cd opencv-3.3.0/samples/cpp/
When I try to build Assimp by running build_ios.sh, it tells me:
CMake Error: your C compiler: "/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/llvm-gcc" was not found. Please set CMAKE_C_COMPILER to a valid compiler path or name.
CMake Error: your CXX compiler: "/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/llvm-g++" was not found. Please set CMAKE_CXX_COMPILER to a valid compiler path or name.
What I need the path to be is:
/Applications/XCode.app/Contents/Developer/Platforms/...
I've tried changing DEVROOT in build_ios.sh and IPHONE_xxxx_TOOLCHAIN.cmake, because that's what CMAKE_C_COMPILER etc seem to get generated from, but it still gives me the same errors.
Option 1:
You can set CMake variables at command line like this:
cmake -D CMAKE_C_COMPILER="/path/to/your/c/compiler/executable" -D CMAKE_CXX_COMPILER "/path/to/your/cpp/compiler/executable" /path/to/directory/containing/CMakeLists.txt
See this to learn how to create a CMake cache entry.
Option 2:
In your shell script build_ios.sh you can set environment variables CC and CXX to point to your C and C++ compiler executable respectively, example:
export CC=/path/to/your/c/compiler/executable
export CXX=/path/to/your/cpp/compiler/executable
cmake /path/to/directory/containing/CMakeLists.txt
Option 3:
Edit the CMakeLists.txt file of "Assimp": Add these lines at the top (must be added before you use project() or enable_language() command)
set(CMAKE_C_COMPILER "/path/to/your/c/compiler/executable")
set(CMAKE_CXX_COMPILER "/path/to/your/cpp/compiler/executable")
See this to learn how to use set command in CMake. Also this is a useful resource for understanding use of some of the common CMake variables.
Here is the relevant entry from the official FAQ: https://gitlab.kitware.com/cmake/community/wikis/FAQ#how-do-i-use-a-different-compiler
The cc and cxx is located inside /Applications/Xcode.app. This should find the right paths
export CXX=`xcrun -find c++`
export CC=`xcrun -find cc`
SOLUTIONS
Sometimes the project is created before installing g++. So install g++ first and then recreate your project. This worked for me.
Paste the following line in CMakeCache.txt:
CMAKE_CXX_COMPILER:FILEPATH=/usr/bin/c++
Note the path to g++ depends on OS. I have used my fedora path obtained using which g++
I am trying to configure util-linux to cross compile using arm-none-linux-gnueabi from CodeSourcery. My only problem so far is that it can't find my ncurses library which I compiled.
How can I add a directory to the ld search path? I've tried adding to my LIBRARY_PATH and LD_LIBRARY_PATH variables, but neither does anything. I know that I can add the -L flag to gcc and it will add to the linker path, but is there any way to do this globally, so that I can do it once, and not have to worry about it again?
Here is the output of arm-none-linux-gnueabi-gcc -print-search-dirs | grep libraries | sed 's/:/\n/g':
libraries
=/tools/bin/../lib/gcc/arm-none-linux-gnueabi/4.6.1/
/tools/bin/../lib/gcc/
/tools/bin/../lib/gcc/arm-none-linux-gnueabi/4.6.1/../../../../arm-none-linux-gnueabi/lib/arm-none-linux-gnueabi/4.6.1/
/tools/bin/../lib/gcc/arm-none-linux-gnueabi/4.6.1/../../../../arm-none-linux-gnueabi/lib/
/tools/bin/../arm-none-linux-gnueabi/libc/lib/arm-none-linux-gnueabi/4.6.1/
/tools/bin/../arm-none-linux-gnueabi/libc/lib/
/tools/bin/../arm-none-linux-gnueabi/libc/usr/lib/arm-none-linux-gnueabi/4.6.1/
/tools/bin/../arm-none-linux-gnueabi/libc/usr/lib/
I would like to add /arm/usr/lib and /arm/usr/local/lib to my ld search path.
If you need output from any other commands, just ask!
EDIT: I just found out about the CFLAGS environment variable--do all configure scripts/makefiles honor it?
Thank you!
If the ncurses library you compiled are going to be linked to the ARM binary you are cross-compiling you can not use LD_LIBRARY_PATH! LD_LIBRARY_PATH is only used by the current run-time and is in no way used by the compiler or linker when building your application.
The use of CFLAGS depends on creator of Makefile. CFLAGS are not automatically used even if they are defined as an environment variable. Only tools like the autoconf tools can pick them up from the environment and use them automagically. In the Makefiles find something like:
$(CC) $(CFLAGS) ....
if this fragment exists then the Makefile uses the CFLAGS variable. LDFLAGS is the more appropriate environment variable to use for link-time options.