# Helper for checking for atomics
function(check_working_cxx_atomics varname additional_lib)
- include(CheckCXXSourceCompiles)
- include(CMakePushCheckState)
- cmake_push_check_state()
- set(CMAKE_REQUIRED_FLAGS "-std=c++11")
- set(CMAKE_REQUIRED_LIBRARIES "${additional_lib}")
- set(CMAKE_REQUIRED_QUIET 1)
- CHECK_CXX_SOURCE_COMPILES("
+ include(CheckCXXSourceCompiles)
+ include(CMakePushCheckState)
+ cmake_push_check_state()
+ set(CMAKE_REQUIRED_FLAGS "-std=c++11")
+ set(CMAKE_REQUIRED_LIBRARIES "${additional_lib}")
+ set(CMAKE_REQUIRED_QUIET 1)
+ CHECK_CXX_SOURCE_COMPILES("
#include <atomic>
std::atomic<int> x;
int main() {
- return std::atomic_fetch_add_explicit(&x, 1, std::memory_order_seq_cst);
+ return std::atomic_fetch_add_explicit(&x, 1, std::memory_order_seq_cst);
}
" ${varname})
- cmake_pop_check_state()
+ cmake_pop_check_state()
endfunction(check_working_cxx_atomics)
# First check if atomics work without the library.
# If not, check if the library exists, and atomics work with it.
check_working_cxx_atomics(HAVE_CXX_ATOMICS_WITHOUT_LIB "")
if(HAVE_CXX_ATOMICS_WITHOUT_LIB)
- message(STATUS "Atomics provided by the C-library - yes")
+ message(STATUS "Atomics provided by the C-library - yes")
else()
- message(STATUS "Atomics provided by the C-library - no")
- find_library(LIBATOMIC_LIBRARY NAMES atomic PATH_SUFFIXES lib)
- if(LIBATOMIC_LIBRARY)
- check_working_cxx_atomics(HAVE_CXX_ATOMICS_WITH_LIB "${LIBATOMIC_LIBRARY}")
- if (HAVE_CXX_ATOMICS_WITH_LIB)
- message(STATUS "Atomics provided by libatomic - yes")
- else()
- message(STATUS "Atomics provided by libatomic - no")
- message(FATAL_ERROR "Compiler must support std::atomic!")
- endif()
- else()
- message(FATAL_ERROR "Compiler appears to require libatomic, but cannot find it.")
- endif()
+ message(STATUS "Atomics provided by the C-library - no")
+ find_library(LIBATOMIC_LIBRARY NAMES atomic PATH_SUFFIXES lib)
+ if(LIBATOMIC_LIBRARY)
+ check_working_cxx_atomics(HAVE_CXX_ATOMICS_WITH_LIB "${LIBATOMIC_LIBRARY}")
+ if (HAVE_CXX_ATOMICS_WITH_LIB)
+ message(STATUS "Atomics provided by libatomic - yes")
+ else()
+ message(STATUS "Atomics provided by libatomic - no")
+ message(FATAL_ERROR "Compiler must support std::atomic!")
+ endif()
+ else()
+ message(FATAL_ERROR "Compiler appears to require libatomic, but cannot find it.")
+ endif()
endif()
# Check availability of features which depend on library versions.