CMake无法找到OpenMP

Question

我正在尝试使用OpenMP进行编译.我CMakeLists.txt包含这条线

find_package(OpenMP REQUIRED)

和CMake错误

CMake Error at /opt/ros/groovy/share/catkin/cmake/catkinConfig.cmake:72 (find_package):
  Could not find a configuration file for package openmp.

  Set openmp_DIR to the directory containing a CMake configuration file for
  openmp.  The file will have one of the following names:

    openmpConfig.cmake
    openmp-config.cmake

检查我的文件系统,我看到我有/usr/share/cmake-2.8/Modules/FindOpenMP.cmake但没有openmpConfig.cmake或openmp-config.cmake.我需要做些什么来解决这个问题？

Answer 1

即使在2.x版本中,CMake也有一个FindOpenMP模块.见http://www.cmake.org/cmake/help/v3.0/module/FindOpenMP.html

所以我会这样做:

OPTION (USE_OpenMP "Use OpenMP" ON)
IF(USE_OpenMP)
  FIND_PACKAGE(OpenMP)
  IF(OPENMP_FOUND)
    SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${OpenMP_C_FLAGS}")
    SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
  ENDIF()
ENDIF()

Answer 2

根据Modern CMake在线书籍，这是使用 CMake 配置 OpenMP 支持的方式：

find_package(OpenMP)
if(OpenMP_CXX_FOUND)
    target_link_libraries(MyTarget PUBLIC OpenMP::OpenMP_CXX)
endif()

您绝对不应该做的是手动添加标志-fopenmp（如接受的答案建议），因为这可能不可移植。

Answer 3

OpenMp不是一个包,如果它是支持的,它作为你的编译器的一部分.尝试设置CMAKE_C_FLAGS或CMAKE_CXX_FLAGS相应.例如:

set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fopenmp")在使用时激活OpenMP用于编译C源gcc.对于其他编译器,您应首先检测编译器,然后添加适当的标志