M300433/cmake improvements and define cleanups

CMakeLists.txt

 cmake_minimum_required( VERSION 3.27 FATAL_ERROR )
 
 message(VERBOSE "Entering libcdi")
-project(libcdi VERSION 2.5.1 LANGUAGES C )
+project(cdilib VERSION 2.5.1 LANGUAGES C )
 set(CMAKE_C_STANDARD 11)
 
 include(CTest)
 include(CheckIncludeFile)
 
+
+# Finding libraries
+### -------------- Pthread ---------------------------
+
+option(enable_pthread "Use the pthread library [default=ON]" ON)
+if(${enable_pthread})
+  include(FindThreads)
+  find_package(Threads REQUIRED)
+  set_target_properties(Threads::Threads PROPERTIES THREADS_PREFER_PTHREAD_FLAG TRUE)
+  list(APPEND cdi_compile_defs HAVE_PTHREAD=1)
+endif()
+
 # enable default internal libs
-add_compile_definitions(HAVE_LIBGRIB=1)
-add_compile_definitions(HAVE_LIBCGRIBEX=1)
-add_compile_definitions(HAVE_LIBEXTRA=1)
-add_compile_definitions(HAVE_LIBSERVICE=1)
-add_compile_definitions(HAVE_LIBIEG=1)
+option(enable_libgrib "GRIB support [default=ON]" ON)
+if(${enable_libgrib})
+  list(APPEND cdi_compile_defs HAVE_LIBGRIB=1)
+endif()
+
+option(enable_cgribex "Use the CGRIBEX library [default=ON]" ON)
+if(${enable_cgribex})
+  list(APPEND cdi_compile_defs LIBCGRIBEX=1)
+endif()
+
+option(enable_extra "Use the extra library [default=ON]" ON)
+if(${enable_extra})
+  list(APPEND cdi_compile_defs HAVE_LIBEXTRA=1)
+endif()
+
+option(enable_ieg "Use the extra library [default=ON]" ON)
+if(${enable_ieg})
+  list(APPEND cdi_compile_defs HAVE_LIBIEG=1)
+endif()
+
+option(enable_service "Use the extra library [default=ON]" ON)
+if(${enable_service})
+  list(APPEND cdi_compile_defs HAVE_LIBSERVICE=1)
+endif()
+
 
 # ecCodes
-find_package(eccodes)
-if (${eccodes_FOUND})
-  add_compile_definitions(HAVE_LIBGRIB_API=${eccodes_FOUND})
-  message(VERBOSE "added compile definition HAVE_LIBGRIB_API=${eccodes_FOUND}")
-else()
-  message(WARNING "netcdf not found, compiling without netcdf")
-endif ()
+option(enable_eccodes "Use the eccodes library [default=ON]" ON)
+if(${enable_eccodes} OR eccodes_ROOT)
+  find_package(eccodes)
+  if (${eccodes_FOUND})
+    list(APPEND cdi_compile_defs HAVE_LIBGRIB_API=${eccodes_FOUND})
+    message(VERBOSE "added compile definition HAVE_LIBGRIB_API=${eccodes_FOUND}")
+  else()
+    message(WARNING "eccodes not found, compiling without eccodes")
+  endif ()
+endif()
 
 # NetCDF
-find_package(netCDF COMPONENTS C REQUIRED)
-check_include_file("netcdf.h" ${netcdf_flag} C)
-if (${netCDF_FOUND})
-  message(VERBOSE "added compile definition HAVE_LIBNETCDF=${netCDF_FOUND}")
-  message(VERBOSE "added compile definition HAVE_NETCDF4=${netCDF_FOUND}")
-  add_compile_definitions(HAVE_LIBNETCDF=${netCDF_FOUND})
-  add_compile_definitions(HAVE_NETCDF4=${netCDF_FOUND})
-else()
-  message(WARNING "netcdf not found, compiling without netcdf")
-endif ()
+option(enable_netcdf "Use the netcdf library [default=ON]" ON)
+if(${enable_netcdf} OR netCDF_ROOT )
+  find_package(netCDF COMPONENTS C REQUIRED)
+  if (TARGET netCDF::netcdf)
+    list(APPEND cdi_compile_defs
+      HAVE_LIBNETCDF=${netCDF_FOUND}
+      HAVE_LIBNC_DAP=${netCDF_FOUND}
+      HAVE_NETCDF4=${netCDF_FOUND}
+      HAVE_LIBGRIB_API=${netCDF_FOUND}
+      HAVE_LIBGRIB=${netCDF_FOUND}
+    )
+  else()
+    message(WARNING "netcdf target not found, compiling without netcdf")
+  endif ()
+endif()
 
 message(VERBOSE "looking for config.h in: ${PROJECT_BINARY_DIR}/src")
-include_directories( "${PROJECT_BINARY_DIR}/src/config.h")
-
 
 #adding subdirectories
 ## lib and general files
+list(APPEND cdi_compile_defs CDI=1 CDI_SIZE_TYPE=size_t PACKAGE_NAME="${PROJECT_NAME}" VERSION="${CMAKE_PROJECT_VERSION}")
 add_subdirectory(src)
-## cdi executable
-add_subdirectory(app)
 
 #tests
-add_subdirectory( tests )
+add_subdirectory(app)
+add_subdirectory(tests)
+
 

[Mathieu Westphal]

I dont think this is correct, netcdf does not provide grib_api.h on my netcdf installation.

[Oliver Heidmann]

Yes, they are internal libraries from us. I need to sort that out later on.

[Mathieu Westphal]

I can try a patch.

[Mathieu Westphal]

!138 (merged)

[Mathieu Westphal]

I think this code is not reachable, as the find_package is REQUIRED.

[Oliver Heidmann]

Why is (enable_netcdf OR netCDF_ROOT) not enough to be able to reach the find_package? I have trouble following you in some cases. Please explain in short why something does not work.

[Mathieu Westphal]

find_package(netCDF COMPONENTS C REQUIRED) will either find netCDF::netcdf or fail with an error right away because of the REQUIRED keyword, which means if (TARGET netCDF::netcdf) is always true, at least according to FindNetCDF.cmake documentation and logic. I just quickly read it to make sure.

By the way it is considered a good practice to use REQUIRED, so I'm not advocating to remove it, however I do think the else() and warning below cannot be reached and can be removed.

[Oliver Heidmann]

Oh you mean the else. Ok that makes sense. Thanks for clarifying.