CMAKE3:将通往MPI标头的路径设置

cmake3: set path to mpi headers

本文关键字：路径 设置 MPI CMAKE3      更新时间：2023-10-16

基于cmake：将路径设置为MPI标题和二进制文件，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})

它效果很好。但是，当我使用cmake3做到：

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

我得到此错误：

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)

有什么想法？

您正在遇到CMP0004策略错误。在较早版本的Cmake中，链接的库会自动删除任何领先或落后的空格。在某些情况下，这可能会导致微妙的，不希望的错误，因此CMake现在执行此策略，NEW行为，要求链接的库具有 no no 领先或落后的空间。看起来您的MPI目标之一就是与此链接，它具有领先的空格字符：

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

基于此CMAKE问题，此策略错误似乎是在CMAKE 3.9开始固定的。如果您正在运行超过3.9的Cmake，则必须修改FindMPI.cmake文件以删除领先的空格，或者您可以告诉CMAKE为此策略使用旧行为(默默删除领先的Whitespace(：

cmake_policy(SET CMP0004 OLD)

这是cmake_policy的文档。在FindMPI.cmake文件中设置此策略的同时，不建议使用。制定了CMAKE策略以避免OLD行为，因此建议您手动从文件手动删除空格。

注意：与不同版本的CMake测试时始终是这种情况，请确保您在切换版本时删除CMake Cache并从刮擦中构建。

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