CMakeLists.txt

cmake_minimum_required(VERSION 3.13)

set(libcaosdb_VERSION 0.0.1)

project(libcaosdb
    VERSION ${libcaosdb_VERSION}
    DESCRIPTION "Plain C client libraries for CaosDB"
    LANGUAGES C)

set(CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/cmake" ${CMAKE_MODULE_PATH})
set(PROJECT_INCLUDE_DIR "${PROJECT_SOURCE_DIR}/include")

add_subdirectory(src)
add_subdirectory(include)
add_subdirectory(doc)

add_library(libcaosdb STATIC ${libcaosdb_INCL} ${libcaosdb_SRC})
add_executable(caosdbcli src/caosdbcli.c)
target_link_libraries(caosdbcli libcaosdb)

if("${CMAKE_BUILD_TYPE}" MATCHES "Debug")
    target_link_libraries(libcaosdb gcov)
    enable_testing()
    add_subdirectory(test)
    append_coverage_compiler_flags()
endif()


# These variables slightly modify the install location to allow for version
# specific installations.
set(libcaosdb_INCLUDE_DEST "include/libcaosdb-${libcaosdb_VERSION}")
set(libcaosdb_LIB_DEST "lib/libcaosdb-${libcaosdb_VERSION}")


# generator expressions are needed for the include directories, since
# installing headers changes the include path specify that libcaosdb requires
# the files located in the include/ directory at compile time. This would
# normally look like
#   target_include_directories(libcaosdb PUBLIC include/)
# PUBLIC means that other libraries including libcaosdb should also include
# the directory include/.
# However, there is a catch. If we are installing the project in
# CMAKE_INSTALL_PREFIX, we can't specify include/ in the build directory: we
# have copied the contents of include to CMAKE_INSTALL_PREFIX/include and we
# would like  other projects to include this directory instead of include/.
# The following CMake command handles this. $<BUILD_INTERFACE:...> and
# $<INSTALL_INTERFACE:...> are macros whose values change depending on if we
# are simply building the code or if we are installing it.
target_include_directories(libcaosdb PUBLIC
   # headers to include when building from source
   $<BUILD_INTERFACE:${libcaosdb_SOURCE_DIR}/include>
   $<BUILD_INTERFACE:${libcaosdb_BINARY_DIR}/include>

   # headers to include when installing  (implicitly prefixes with ${CMAKE_INSTALL_PREFIX}).
   $<INSTALL_INTERFACE:include> 
   )


# Install libcaosdb in CMAKE_INSTALL_PREFIX (defaults to /usr/local on linux).
# To change the install location, run
#   cmake -DCMAKE_INSTALL_PREFIX=<desired-install-path> ..

# install(...) specifies installation rules for the project. It can specify
# location of installed files on the system, user permissions, build
# configurations, etc. Here, we are only copying files.
# install(TARGETS ...) specifies rules for installing targets.
# Here, we are taking a target or list of targets (libcosdb) and telling
# CMake the following:
#   - put shared libraries associated with libcaosdb in ${libcaosdb_LIB_DEST}
#   - put static libraries associated with libcaosdb in ${libcaosdb_LIB_DEST}
#   - put include files associated with libcaosdb in ${libcaosdb_INCLUDE_DEST}
# We also need to specify the export that is associated with libcaosdb; an
# export is just a list of targets to be installed. So we are associating
# libcaosdb with libcaosdbTargets.
install(
    # targets to install
    TARGETS libcaosdb
    # name of the CMake "export group" containing the targets we want to install
    EXPORT libcaosdbTargets
    # Dynamic, static library and include destination locations after running
    # "make install"
    LIBRARY DESTINATION ${libcaosdb_LIB_DEST}
    ARCHIVE DESTINATION ${libcaosdb_LIB_DEST}
    INCLUDES DESTINATION ${libcaosdb_INCLUDE_DEST}
    )


# We now need to install the export libcaosdbTargets that we defined above.
# This is needed in order for another project to import libcaosdb using
#   find_package(libcaosdb)
# find_package(libcaosdb) will look for libcaosdb-config.cmake to provide
# information about the targets contained in the project libcaosdb.
# Fortunately, this is specified in the export libcaosdbTargets, so we will
# install this too.
# install(EXPORT ...) will install the information about an export. Here, we
# save it to a file {$libcaosdb_LIB_DEST}/libcaosdbTargets.cmake and prepend
# everything inside libcaosdbTargets  with the namespace libcaosdb::.
install(
    # The export we want to save (matches name defined above containing the
    # install targets)
    EXPORT libcaosdbTargets
    # CMake file in which to store the export's information
    FILE  libcaosdbTargets.cmake
    # Namespace prepends all targets in the export (when we import later, we
    # will use libcaosdb::libcaosdb)
    NAMESPACE libcaosdb::
    # where to place the resulting file (here, we're putting it with the library)
    DESTINATION ${libcaosdb_LIB_DEST}
    )

# install(FILES ...) simply puts files in a certain place with certain
# properties. We're just copying them to the desired place here.
install(FILES ${libcaosdb_INC} DESTINATION ${libcaosdb_INCLUDE_DEST})