CODEWITHSUNDEEP
cmake
Martin Ueding
Martin Ueding

Reputation: 8719

Manually do the work of find_package by specifying the paths ons the command line

A colleague has a project which uses a hand-written Makefile with hard-coded library paths. So for instance the CXXFLAGS and the LDFLAGS are set like the following:

-I/home/personA/libraries/eigen-3.2.7
-I/home/personA/libraries/boost_1_60_0
-I/home/personB/hdf5-1.8.17/include

-L/home/personA/libraries/boost_1_60_0/stage/lib/
-L/home/personB/hdf5-1.8.17/lib

Nobody has direct administrative rights on this machine, so just installing the Debian packages with those libraries will involve nagging the administrator to install them. And even if he does, there might be a different dependency that is not in the repositories.

In my CMake file, I have this:

find_package(HDF5 REQUIRED COMPONENTS C CXX)
include_directories(${HDF5_INCLUDE_DIRS})

find_package(Boost REQUIRED COMPONENTS filesystem system program_options)

find_package(Eigen3 REQUIRED)
include_directories(SYSTEM ${EIGEN3_INCLUDE_DIR})

find_package(OpenMP)
set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${OpenMP_C_FLAGS}")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")

On my Fedora workstation, this works just fine. On my Ubuntu 14.04 virtual machine, it also works, it also builds on Travis CI. However, this project runs on our compute cluster and the dependencies are in really odd places.

So I would like to invoke cmake in a way that tells it that I already know that include and library flags it needs and not even bother to look for a FindEigen3.cmake file (which is not there).

Is there some way to override the find_package and just specify the paths manually?

Upvotes: 1

Views: 977

Answers (2)

Martin Ueding
Martin Ueding

Reputation: 8719

Just let the user set the variables that find_package would set manually. Then skip the find_package altogether:

if(NOT DEFINED EIGEN3_INCLUDE_DIRS)
    find_package(Eigen3 REQUIRED)
endif()
include_directories(SYSTEM ${EIGEN3_INCLUDE_DIRS})

This has the advantage that one does not even need an FindEigen3.cmake file.

Upvotes: 0

Florian
Florian

Reputation: 42972

You can take advantage of the fact that find_package() does only look for the libraries/include paths until it has found the requested package and stores a successful finding fact in _FOUND variables.

So in your case - taken the Eigen3 example - you can do:

> cmake -D Eigen3_FOUND:BOOL=ON -D EIGEN3_INCLUDE_DIR:PATH=/home/personA/libraries/eigen-3.2.7 ..

Upvotes: 1

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