Question

基于CMake: set path to MPI headers and binaries manually，我将cmake文件设置为：

CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
SET(TARGET "test")
PROJECT(${TARGET})
add_compile_options(-std=c++11)
set(CMAKE_CXX_FLAGS "-std=c++11" CACHE STRING "compile flags" FORCE)

find_package(MPI REQUIRED)
if (MPI_FOUND)
    include_directories(SYSTEM ${MPI_INCLUDE_PATH})
else (MPI_FOUND)
    message(SEND_ERROR "couldn't find MPI")
endif (MPI_FOUND)
add_executable(${TARGET} somefiles)
target_link_libraries(${TARGET} ${MPI_LIBRARIES})

，效果很好。但是当我用cmake3这样做时：

CMAKE_MINIMUM_REQUIRED(VERSION 3.13.4)
the rest is the same as above

我收到此错误：

CMake Error at /home/nourisaj/c++/WP1/build/CMakeFiles/CMakeTmp/cmTC_3d1ffTargets.cmake:16 (add_library):
  Target "MPI::MPI_C" links to item " -Wl,-rpath -Wl,/usr/lib64/openmpi/lib
  -Wl,--enable-new-dtags" which has leading or trailing whitespace.  This is
  now an error according to policy CMP0004.
Call Stack (most recent call first):
  /home/nourisaj/c++/WP1/build/CMakeFiles/CMakeTmp/CMakeLists.txt:14 (include)


CMake Error at /home/nourisaj/c++/WP1/build/CMakeFiles/CMakeTmp/cmTC_3d1ffTargets.cmake:16 (add_library):
  Target "MPI::MPI_C" links to item " -Wl,-rpath -Wl,/usr/lib64/openmpi/lib
  -Wl,--enable-new-dtags" which has leading or trailing whitespace.  This is
  now an error according to policy CMP0004.
Call Stack (most recent call first):
  /home/nourisaj/c++/WP1/build/CMakeFiles/CMakeTmp/CMakeLists.txt:14 (include)


CMake Error at /usr/share/cmake3/Modules/FindMPI.cmake:1187 (try_compile):
  Failed to generate test project build system.
Call Stack (most recent call first):
  /usr/share/cmake3/Modules/FindMPI.cmake:1228 (_MPI_try_staged_settings)
  /usr/share/cmake3/Modules/FindMPI.cmake:1488 (_MPI_check_lang_works)
  CMakeLists.txt:19 (find_package)

有什么主意吗？

Answer 1

您遇到CMP0004策略错误。在早期版本的CMake中，链接库会自动删除任何前导或尾随空格。在某些情况下，这可能导致微妙的，不希望的错误，因此CMake现在强制执行此策略，NEW行为要求链接库的前导或尾随空格为 no 。看来您的MPI目标之一与此链接在一起，它具有领先的空白字符：

" -Wl,-rpath -Wl,/usr/lib64/openmpi/lib -Wl,--enable-new-dtags"

基于此CMake issue，此策略错误似乎已从CMake 3.9开始修复。如果您运行的CMake早于3.9，则必须自行修改FindMPI.cmake文件以删除前导空白，或者您可以告诉CMake使用旧行为执行此策略（静默删除前导空白））：

cmake_policy(SET CMP0004 OLD)

以下是cmake_policy的文档。虽然可以在FindMPI.cmake文件中设置此策略，但不建议这样做。部署CMake策略是为了避免OLD的行为，因此建议您从文件中手动删除空格。

注意：与使用不同版本的CMake进行测试时一样，请确保在删除版本时要删除CMake缓存并从头开始构建。

cmake3：设置mpi标头的路径

1 个答案: