Transitive RPATH property in CMake

Question

Transitive RPATH property in CMake

I am creating a library that I link with several tests and sample programs. The project boasts the cmake property BUILD_SHARED_LIBS

, creating .so

if enabled and creating a file .a

if disabled. The library depends on several other dynamic libraries to be found using an environment variable LIBLOC

(their convention, not mine).

When I create a dynamic version of a library, I can tweak the installation rpath so that the libraries are found correctly. For example:.

add_library(lib ${SRC})
set_target_properties(lib INSTALL_RPATH $LIBLOC)
install(TARGETS lib LIBRARY DESTINATION lib)

And then in each CMakeLists.txt test / example program:

add_executable(test ${SRC})
target_link_libraries(test lib)
set_target_properties(test INSTALL_RPATH $ORIGIN/../lib)
install(TARGETS test RUNTIME bin)

When BUILD_SHARED_LIBS

enabled, the test program is happy:

$ lddtree bin/test
test => bin/test (interpreter => /lib64/ld-linux-x86-64.so.2)
    liblib.so => /path/to/install/liblib.so
        libdep.so => /path/to/dependency/libdep.so

We can find everything because the rpath in the test $ORIGIN/../lib

that finds liblib.so

and then the rpath to liblib.so

is equal $LIBLOC

to which is set in my environment to /path/to/dependency

.

I would expect that when installing the static library, cmake will read the property INSTALL_RPATH

from my library and put it in the test program so that the rpath in the test is $ORIGIN/../lib;$LIBLOC

. Instead, it $LIBLOC

does not fall into any rpath.

My current solution is unsatisfactory: I set mine INSTALL_RPATH

to BUILD_SHARED_LIBS

in every example or test program like

if (BUILD_SHARED_LIBS)
  set_target_properties(test INSTALL_RPATH "$ORIGIN/../lib")
else ()
  set_target_properties(test INSTALL_RPATH "$LIBLOC")
endif ()