improve use as child project

CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.19...3.29)
+cmake_minimum_required(VERSION 3.19...3.30)
 
 if(CMAKE_SOURCE_DIR STREQUAL CMAKE_BINARY_DIR)
   message(FATAL_ERROR "In-source builds are not allowed. Do like:
@@ -27,19 +27,19 @@ file(GENERATE OUTPUT .gitignore CONTENT "*")
 if(find)
   find_package(NetCDF COMPONENTS C Fortran)
 endif()
-if(NOT NetCDF_FOUND)
+if(NOT NetCDF_FOUND AND NOT TARGET NetCDF::NetCDF_Fortran)
   include(cmake/netcdf.cmake)
 endif()
 
 # --- code coverage
-if(${PROJECT_NAME}_COVERAGE AND ${PROJECT_NAME}_IS_TOP_LEVEL)
+if(nc4fortran_COVERAGE AND nc4fortran_IS_TOP_LEVEL)
   include(cmake/Modules/CodeCoverage.cmake)
   append_coverage_compiler_flags()
   set(COVERAGE_EXCLUDES ${PROJECT_SOURCE_DIR}/test)
 endif()
 
 # --- clang-tidy
-if(tidy AND ${PROJECT_NAME}_IS_TOP_LEVEL)
+if(tidy AND nc4fortran_IS_TOP_LEVEL)
   find_program(CLANG_TIDY_EXE NAMES "clang-tidy" REQUIRED)
   set(CMAKE_C_CLANG_TIDY ${CLANG_TIDY_EXE})
 endif()
@@ -66,7 +66,7 @@ target_link_libraries(nc4fortran::nc4fortran INTERFACE nc4fortran)
 
 install(FILES ${CMAKE_CURRENT_BINARY_DIR}/include/nc4fortran.mod TYPE INCLUDE)
 
-install(TARGETS nc4fortran EXPORT ${PROJECT_NAME}-targets)
+install(TARGETS nc4fortran EXPORT nc4fortran-targets)
 
 # additional Find*.cmake necessary
 install(FILES
@@ -76,7 +76,7 @@ DESTINATION cmake
 )
 
 
-if(${PROJECT_NAME}_BUILD_TESTING)
+if(nc4fortran_BUILD_TESTING)
   add_subdirectory(test)
 endif()
 

cmake/FindNetCDF.cmake

@@ -40,8 +40,7 @@ Search details:
 
 #]=======================================================================]
 
-include(CheckCSourceCompiles)
-include(CheckFortranSourceCompiles)
+include(CheckSourceCompiles)
 
 function(netcdf_c)
 
@@ -77,7 +76,7 @@ if(UNIX)
   list(APPEND CMAKE_REQUIRED_LIBRARIES m)
 endif()
 
-check_c_source_compiles(
+check_source_compiles(C
 [=[
 #include <netcdf.h>
 #include <stdio.h>
@@ -132,13 +131,12 @@ set(CMAKE_REQUIRED_FLAGS)
 set(CMAKE_REQUIRED_INCLUDES ${NetCDF_Fortran_INCLUDE_DIR})
 list(INSERT CMAKE_REQUIRED_LIBRARIES 0 ${NetCDF_Fortran_LIBRARY})
 
-check_fortran_source_compiles(
+check_source_compiles(Fortran
 "program a
 use netcdf
 implicit none
 end program"
 NetCDF_Fortran_links
-SRC_EXT f90
 )
 
 if(NOT NetCDF_Fortran_links)

options.cmake

@@ -1,20 +1,10 @@
 message(STATUS "${PROJECT_NAME} ${PROJECT_VERSION} CMake ${CMAKE_VERSION} Toolchain ${CMAKE_TOOLCHAIN_FILE}")
 
-option(${PROJECT_NAME}_COVERAGE "Code coverage tests")
+option(nc4fortran_COVERAGE "Code coverage tests")
 option(tidy "Run clang-tidy on the code")
 option(find "find NetCDF libraries" ON)
 
-if(CMAKE_VERSION VERSION_LESS 3.21)
-  get_property(not_top DIRECTORY PROPERTY PARENT_DIRECTORY)
-  if(not_top)
-    set(${PROJECT_NAME}_IS_TOP_LEVEL false)
-  else()
-    set(${PROJECT_NAME}_IS_TOP_LEVEL true)
-  endif()
-endif()
-
-
-option(${PROJECT_NAME}_BUILD_TESTING "Build tests" ${${PROJECT_NAME}_IS_TOP_LEVEL})
+option(nc4fortran_BUILD_TESTING "Build tests" ${nc4fortran_IS_TOP_LEVEL})
 option(CMAKE_TLS_VERIFY "Verify TLS certificates when downloading libraries" ON)
 
 set_property(DIRECTORY PROPERTY EP_UPDATE_DISCONNECTED true)