I have a very simple CMakeLists.txt for a C++ project, which builds a shared library:
add_library(foo SHARED
${HDR_PUBLIC}
${SOURCES})
When linking the library, CMake automatically uses -lstdc++. How can I stop it from doing this?
You can add -stdlib=libc++ to compiler flags.
Simple example:
cmake_minimum_required(VERSION 2.8.4)
project(test)
set(CMAKE_VERBOSE_MAKEFILE TRUE)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -v -stdlib=libc++")
add_executable(test main.cpp)
Give output:
"/usr/bin/ld" ... -o test ... -lc++ ...
By default:
cmake_minimum_required(VERSION 2.8.4)
project(test)
set(CMAKE_VERBOSE_MAKEFILE TRUE)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -v")
add_executable(test main.cpp)
Link to stdc++:
"/usr/bin/ld" ... -o test ... -lstdc++ ...
[update]
If you don't need to link to c++ lib at all - use '-nodefaultlibs' as linker flag and '-nostdinc++' to compiler flag. You may need to link some default libraries, like '-lSystem'.
set(CMAKE_CXX_IMPLICIT_LINK_LIBRARIES "")
set(CMAKE_CXX_IMPLICIT_LINK_DIRECTORIES "")
set_target_properties(yourtarget PROPERTIES LINKER_LANGUAGE C)
Source: http://cmake.3232098.n2.nabble.com/setting-LINKER-LANGUAGE-still-adds-lstdc-td7581940.html
Related
I am adapting Sascha Willems' Vulkan Samples to compile shaders when ever i build the program. I know this question has been asked a lot but none of the solutions I found worked for me.
Here is my code:
cmake_minimum_required(VERSION 3.19)
project(Test)
set( ${CMAKE_CURRENT_SOURCE_DIR}/shaders)
set(SHADER_DIR ${CMAKE_CURRENT_SOURCE_DIR}/shaders)
file(GLOB SHADERS ${SHADER_DIR}/*.vert ${SHADER_DIR}/*.frag ${SHADER_DIR}/*.comp ${SHADER_DIR}/*.geom ${SHADER_DIR}/*.tesc ${SHADER_DIR}/*.tese ${SHADER_DIR}/*.mesh ${SHADER_DIR}/*.task ${SHADER_DIR}/*.rgen ${SHADER_DIR}/*.rchit ${SHADER_DIR}/*.rmiss)
file(GLOB SPV_SHADERS ${SHADER_DIR}/*.spv)
find_package(Vulkan)
foreach(SHADER IN LISTS SHADERS)
get_filename_component(FILENAME ${SHADER} NAME)
add_custom_command(OUTPUT ${SHADER_DIR}/shaders/${FILENAME}.spv
COMMAND ${Vulkan_GLSLC_EXECUTABLE} ${SHADER} -o ${SHADER_DIR}/shaders/${FILENAME}.spv
DEPENDS ${SHADER}
COMMENT "Compiling ${FILENAME}")
endForeach()
add_custom_target(shaders ALL DEPENDS ${SPV_SHADERS})
add_executable(Test main.cpp ${SHADERS})
add_dependencies(Test shaders)
[Edit]: CMake seems to skip the foreach loop am I using it correctly?
[Edit2]: Now the loop works but the shaders are still not compiling
After searching a bit, I deleted file(GLOB SPV_SHADERS ${SHADER_DIR}/*.spv) and replaced it with list(APPEND SPV_SHADERS ${ASSETS_DIR}/shaders/${FILENAME}.spv)
It would look like this:
cmake_minimum_required(VERSION 3.19)
project(Test)
set( ${CMAKE_CURRENT_SOURCE_DIR}/shaders)
set(SHADER_DIR ${CMAKE_CURRENT_SOURCE_DIR}/shaders)
file(GLOB SHADERS ${SHADER_DIR}/*.vert ${SHADER_DIR}/*.frag ${SHADER_DIR}/*.comp ${SHADER_DIR}/*.geom ${SHADER_DIR}/*.tesc ${SHADER_DIR}/*.tese ${SHADER_DIR}/*.mesh ${SHADER_DIR}/*.task ${SHADER_DIR}/*.rgen ${SHADER_DIR}/*.rchit ${SHADER_DIR}/*.rmiss)
find_package(Vulkan)
foreach(SHADER IN LISTS SHADERS)
get_filename_component(FILENAME ${SHADER} NAME)
add_custom_command(OUTPUT ${SHADER_DIR}/shaders/${FILENAME}.spv
COMMAND ${Vulkan_GLSLC_EXECUTABLE} ${SHADER} -o ${SHADER_DIR}/shaders/${FILENAME}.spv
DEPENDS ${SHADER}
COMMENT "Compiling ${FILENAME}")
list(APPENDS SPV_SHADERS ${SHADER_DIR}/shaders/${FILENAME}.spv)
endForeach()
add_custom_target(shaders ALL DEPENDS ${SPV_SHADERS})
add_executable(Test main.cpp ${SHADERS})
add_dependencies(Test shaders)
I am building a python extension from c++ shared library.
This library is using some openmp pragma.
I would like to know how to configure CMakeLists.txt in order to include openmp ?
I have added the openmp flag -fopenmp
But I still have this error : undefined symbol: GOMP_critical_end
here is my CMakeLists.txt file
cmake_minimum_required(VERSION 3.10)
set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++lastest -pthread -fopenmp")
project (py_interface)
#find_library('gomp')
find_package(OpenMP REQUIRED)
find_package(Boost REQUIRED)
include_directories(/usr/include/python3.6/)
link_directories(/usr/local/lib)
set(SRC interface.cpp)
add_library(py_interface SHARED ${SRC})
target_link_libraries(py_interface PRIVATE OpenMP::OpenMP_CXX ${PYTHON_LIBRARIES} ${Boost_LIBRARIES})
set_property(TARGET py_interface PROPERTY POSITION_INDEPENDENT_CODE ON)
I'm doing C++ using libcURL. I got the task to test functions in Travis CI. So I used .travis.yml to get libcurl-dev and libssl-dev to connect to the project. I installed them and checked cURL configuration:
SSL support: enabled (OpenSSL)
But as I was trying to make main test file i got list of errors (example)
`Linking CXX executable ../bin/TechProject_example
/usr/local/lib/libcurl.a(libcurl_la-openssl.o): In function ossl_recv:
openssl.c:(.text+0xf3): undefined reference to ERR_clear_error
openssl.c:(.text+0x11c): undefined reference to SSL_read
openssl.c:(.text+0x163): undefined reference to SSL_get_error`
and so on...
The only thing I was able to check is that libcurl is working properly. I placed
--without-ssl flag and got protocol error.
Also I used
`- sudo ln -fs /usr/lib/libcurl.so.4 /usr/local/lib/`
to avoid cmake error. (I'm not very good at UNIX command, so this can be a problem)
So how should properly connect openSSL to C++ project that has <curl/curl.h> ?
EDIT:
Here is CMakeLists.txt:
cmake_minimum_required(VERSION 2.8)
project (TechProject)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
set(HEADERS ${PROJECT_SOURCE_DIR}/include/testclass.h)
set(HEADERS ${PROJECT_SOURCE_DIR}/include/catch.hpp)
set(SOURCES ${PROJECT_SOURCE_DIR}/sources/testclass.cpp)
set(EXECUTABLE_OUTPUT_PATH ${PROJECT_BINARY_DIR}/bin)
set(LIBRARY_OUTPUT_PATH ${PROJECT_BINARY_DIR}/lib)
include_directories(${PROJECT_SOURCE_DIR}/include)
add_library (${PROJECT_NAME} STATIC ${SOURCES})
add_subdirectory(example)
add_subdirectory(tests)
find_library(FOO_LIB libcurl.a)
target_link_libraries(TechProject "${FOO_LIB}")
And CMakeLists.txt in tests subdir:
cmake_minimum_required(VERSION 2.8)
set(TESTS_FOR_PROJECT TechProject)
project(${TESTS_FOR_PROJECT}_tests)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
option(BUILD_SHARED_LIBS "Build shared instead of static library" OFF)
file(GLOB ${PROJECT_NAME}_sources "${CMAKE_CURRENT_SOURCE_DIR}/source/*.cpp")
find_package(${TESTS_FOR_PROJECT})
include_directories(${${TESTS_FOR_PROJECT}_INCLUDE_DIRS}})
include_directories(${CPM_INCLUDE_DIRS})
add_executable(${PROJECT_NAME} ${${PROJECT_NAME}_sources} ${${PROJECT_NAME}_headers})
target_link_libraries(${PROJECT_NAME} ${TESTS_FOR_PROJECT})
add_custom_command(TARGET ${PROJECT_NAME} PRE_BUILD
COMMAND ${CMAKE_COMMAND} -E copy_directory
${CMAKE_CURRENT_SOURCE_DIR}/fixtures $<TARGET_FILE_DIR:${PROJECT_NAME}>)
add_custom_command(TARGET ${PROJECT_NAME} POST_BUILD COMMAND ${PROJECT_NAME} -s -r compact WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
I'm trying to build a project (with CLion) with the following CMakeLists.txt:
cmake_minimum_required(VERSION 3.6)
project(alfa_1)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c11 -Wall -Wextra -lm")
set(SOURCE_FILES
src/foo.h
src/foo.c
src/bar.h
src/bar.c
src/parser.h
src/parser.c)
add_executable(alfa_1 ${SOURCE_FILES})
In foo.c I use pow() function from math.h, which I include in foo.h. And obviously foo.h is included in foo.c. In bar.c I have main that is doing nothing. Now, standard command line compilation like this
gcc -o bar bar.c bar.h foo.h foo.c -lm
works fine but building the project yields undefined reference to pow. As one can see I included -lm flag in CmakeLists.txt file, so I don't get why this linking part is not working here
CMAKE_CXX_FLAGS are flags for the C++ compiler. -l is a linker flag. To link to a library, use this:
target_link_libraries(alfa_1 m)
You might also want to replace -std=c11 with use of CMAKE_C_STANDARD and related variables (CMAKE_C_STANDARD_REQUIRED, CMAKE_C_EXTENSIONS), and possibly replace use of CMAKE_CXX_FLAGS with a call to target_compile_options().
add the link of library in the cmakeList
add_library(math STATIC path/to/file.cpp)
add_executable(cmake_hello main.cpp)
target_link_libraries(cmake_hello math)
and in the class cpp
#include "path/to/file.hpp"
for mode detaills see this link
In Clion this configuration solved my problem:
cmake_minimum_required(VERSION 3.13)
project(K_Nearest C)
set(CMAKE_C_STANDARD 99)
add_executable(K_Nearest main.c point.h point.c group.c group.h)
target_link_libraries(K_Nearest m)
The important step was: target_link_libraries(K_Nearest m), it should come after add_executable(...) statement.
I'm trying to use LTO in clang (with cmake): flag -emit-llvm set in compile time, output generated with -c flag, so LLVM bitcode is the result. The problem is, cmake give me result with ".o" suffix, but i need ".bc". I found other codes that used this: set(CMAKE_C_OUTPUT_EXTENSION .bc), but it didn't work.
cmake_minimum_required(VERSION 3.3)
project(cc C)
set(CMAKE_BUILD_TYPE Release)
enable_language(C)
file(GLOB_RECURSE SOURCES "src/*.c")
add_executable(cc ${SOURCES})
if (UNIX)
target_compile_options(cc PRIVATE "-Weverything")
target_compile_options(cc PRIVATE "-std=c11")
target_compile_options(cc PRIVATE "-emit-llvm")
set(CMAKE_C_FLAGS_RELEASE "-Ofast -DNDEBUG")
set(CMAKE_C_OUTPUT_EXTENSION ".bc")
endif()