我正在使用CMake（版本3.20.1）构建ScaLAPACK（提交7e4e07070a489686287c36ab473d21cf29a54bdd）。find_package实用程序在CMakeLists.txt中用于定义使用MPI编译所需的库、包含目录和标志。ScaLAPACK库使用别名MPI::MPI_C与MPI链接：

target_link_libraries( scalapack ${LAPACK_LIBRARIES} ${BLAS_LIBRARIES} MPI::MPI_C)

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我正在构建一个共享库，因此根据CMake default behavior，生成的DSO在其RPATH中不应该有任何条目。但是，已安装的库DSO在其RUNPATH中维护以下条目：

$ readelf -d ~/opt/scalapack/lib/libscalapack.so | grep RUNPATH
 0x000000000000001d (RUNPATH)            Library runpath: [/opt/apps/resif/aion/2020b/epyc/software/UCX/1.9.0-GCCcore-10.2.0/lib64:/usr/lib64:/opt/apps/resif/aion/2020b/epyc/software/OpenMPI/4.0.5-GCC-10.2.0/lib]

型
如果使用find_package实用程序定义的库变量MPI_C_LIBRARIES将库与链接，

target_link_libraries( scalapack ${LAPACK_LIBRARIES} ${BLAS_LIBRARIES} ${MPI_C_LIBRARIES})

型
则在已安装的DSO中没有RUNPATH条目。
进一步查看CMake生成的Makefile，我注意到以下差异：

• 别名为MPI::MPI_C：

# File: <build directory>/CMakeFiles/scalapack.dir/DependInfo.cmake
...
set(CMAKE_Fortran_TARGET_INCLUDE_PATH
  "/mnt/irisgpfs/apps/resif/aion/2020b/epyc/software/OpenMPI/4.0.5-GCC-10.2.0/include"
  "/opt/apps/resif/aion/2020b/epyc/software/OpenMPI/4.0.5-GCC-10.2.0/include"
)
...

# File: <build directory>/CMakeFiles/scalapack.dir/Dflags.make
...
C_INCLUDES = -isystem /opt/apps/resif/aion/2020b/epyc/software/OpenMPI/4.0.5-GCC-10.2.0/include

C_FLAGS = -O3 -DNDEBUG -fPIC -fexceptions

Fortran_DEFINES = -DAdd_ -Dscalapack_EXPORTS

Fortran_INCLUDES = -I/mnt/irisgpfs/apps/resif/aion/2020b/epyc/software/OpenMPI/4.0.5-GCC-10.2.0/include -I/opt/apps/resif/aion/2020b/epyc/software/OpenMPI/4.0.5-GCC-10.2.0/include

Fortran_FLAGS = -fallow-argument-mismatch -O2 -DNDEBUG -O2 -fPIC -fexceptions
...

# File: <build directory>/CMakeFiles/scalapack.dir/link.txt

/opt/apps/resif/aion/2020b/epyc/software/GCCcore/10.2.0/bin/gfortran -fPIC -fallow-argument-mismatch -O2 -DNDEBUG -O2 -Wl,-rpath -Wl,/opt/apps/resif/aion/2020b/epyc/software/UCX/1.9.0-GCCcore-10.2.0/lib64 -Wl,-rpath -Wl,/usr/lib64 -Wl,-rpath -Wl,/opt/apps/resif/aion/2020b/epyc/software/OpenMPI/4.0.5-GCC-10.2.0/lib -Wl,--enable-new-dtags -L/mnt/irisgpfs/apps/resif/aion/2020b/epyc/software/UCX/1.9.0-GCCcore-10.2.0/lib -L/usr/lib64 -L/mnt/irisgpfs/apps/resif/aion/2020b/epyc/software/OpenMPI/4.0.5-GCC-10.2.0/lib -shared -Wl,-soname,libscalapack.so.2.2 -o lib/libscalapack.so.2.2.1 @CMakeFiles/scalapack.dir/objects1.rsp  -Wl,-rpath,/home/users/gkafanas/opt/openblas/lib64: /home/users/gkafanas/opt/openblas/lib64/libopenblas.so -lpthread -lm -ldl /home/users/gkafanas/opt/openblas/lib64/libopenblas.so -lpthread -lm -ldl /opt/apps/resif/aion/2020b/epyc/software/OpenMPI/4.0.5-GCC-10.2.0/lib/libmpi.so

型

• 使用变量MPI_C_LIBRARIES：

# File: <build directory>/CMakeFiles/scalapack.dir/DependInfo.cmake
...
set(CMAKE_Fortran_TARGET_INCLUDE_PATH
)
...

# File: <build directory>/CMakeFiles/scalapack.dir/Dflags.make
...
C_INCLUDES = 

C_FLAGS = -O3 -DNDEBUG -fPIC

Fortran_DEFINES = -DAdd_ -Dscalapack_EXPORTS

Fortran_INCLUDES = 

Fortran_FLAGS = -fallow-argument-mismatch -O2 -DNDEBUG -O2 -fPIC
...

# File: <build directory>/CMakeFiles/scalapack.dir/link.txt

/opt/apps/resif/aion/2020b/epyc/software/GCCcore/10.2.0/bin/gfortran -fPIC -fallow-argument-mismatch -O2 -DNDEBUG -O2 -shared -Wl,-soname,libscalapack.so.2.2 -o lib/libscalapack.so.2.2.1 @CMakeFiles/scalapack.dir/objects1.rsp  -Wl,-rpath,/home/users/gkafanas/opt/openblas/lib64: /home/users/gkafanas/opt/openblas/lib64/libopenblas.so -lpthread -lm -ldl /home/users/gkafanas/opt/openblas/lib64/libopenblas.so /opt/apps/resif/aion/2020b/epyc/software/OpenMPI/4.0.5-GCC-10.2.0/lib/libmpi.so -lpthread -lm -ldl /opt/apps/resif/aion/2020b/epyc/software/OpenMPI/4.0.5-GCC-10.2.0/lib/libmpi.so

型
所以看起来别名设置了一些不必要的系统选项。
我有两个问题：
1.别名MPI::MPI_C是什么以及如何使用它。
1.为什么别名如此设置参数，而有人可能期望它只设置用于将ScaLAPACK DSO与MPI链接的变量。