add Fortran submodule example

Author: scivision

.github/workflows/ci_cmake.yml

@@ -23,6 +23,7 @@ jobs:
     strategy:
       matrix:
         gcc-version: [7, 8, 9, 10, 11]
+        shared: [true, false]
 
     env:
       CC: gcc-${{ matrix.gcc-version }}
@@ -36,11 +37,9 @@ jobs:
         sudo apt update
         sudo apt install ninja-build gcc-${{ matrix.gcc-version }} g++-${{ matrix.gcc-version }} gfortran-${{ matrix.gcc-version }}
 
-
     - uses: actions/checkout@v2
 
-
-    - run: cmake --preset multi
+    - run: cmake --preset multi -DBUILD_SHARED_LIBS:BOOL=${{ matrix.shared }}
 
     - run: cmake --build --preset debug
     - run: ctest --preset debug -V
@@ -70,7 +69,7 @@ jobs:
         sudo apt update
         sudo apt install ninja-build clang-${{ matrix.clang-version }}
 
-    - run: cmake --preset multi
+    - run: cmake --preset multi -DBUILD_SHARED_LIBS:BOOL=${{ matrix.shared }}
 
     - run: cmake --build --preset debug
     - run: ctest --preset debug -V
@@ -87,6 +86,7 @@ jobs:
     strategy:
       matrix:
         compiler: [ {cpp: g++-11, c: gcc-11}, {cpp: clang++, c: clang} ]
+        shared: [true,false]
 
     env:
       FC: gfortran-11
@@ -99,7 +99,7 @@ jobs:
 
     - uses: actions/checkout@v2
 
-    - run: cmake --preset multi
+    - run: cmake --preset multi -DBUILD_SHARED_LIBS:BOOL=${{ matrix.shared }}
 
     - run: cmake --build --preset debug
     - run: ctest --preset debug -V
@@ -113,12 +113,20 @@ jobs:
     runs-on: windows-latest
     timeout-minutes: 10
 
+    strategy:
+      matrix:
+        compiler: [ {cpp: g++, c: gcc} ]
+        shared: [true,false]
+
     env:
       CMAKE_GENERATOR: MinGW Makefiles
+      FC: gfortran
+      CC: ${{ matrix.compiler.c }}
+      CXX: ${{ matrix.compiler.cpp }}
 
     steps:
     - uses: actions/checkout@v2
 
-    - run: cmake -Bbuild
+    - run: cmake -Bbuild -DBUILD_SHARED_LIBS:BOOL=${{ matrix.shared }}
     - run: cmake --build build
     - run: ctest --test-dir build --preset default

.github/workflows/intel-oneapi.yml

@@ -20,6 +20,10 @@ on:
 jobs:
 
   linux-intel-oneapi:
+    strategy:
+      matrix:
+        shared: [true,false]
+
     runs-on: ubuntu-latest
     timeout-minutes: 10
 
@@ -45,7 +49,7 @@ jobs:
         printenv >> $GITHUB_ENV
 
     - name: Configure multi
-      run: cmake --preset multi
+      run: cmake --preset multi -DBUILD_SHARED_LIBS:BOOL=${{ matrix.shared }}
 
     - name: print config log
       if: ${{ failure() }}

README.md

@@ -26,7 +26,13 @@ We CI test with compilers including:
 * Clang ≥ 6
 * Intel oneAPI
 
-In general, strongly avoid the FortranCInterface of CMake and mangling function names--just use Fortran 2003 standard `bind(C)`
+In general, strongly avoid the FortranCInterface of CMake and mangling function names--just use Fortran 2003 standard `bind(C)`.
+
+## Examples
+
+C++ examples include [./cxx/vector_main.cxx](vector_main.cxx) that shows using a C++ contiguous
+[std::vector](https://en.cppreference.com/w/cpp/container/vector)
+to pass 1-D arrays to/from Fortran.
 
 ## build
 
@@ -46,8 +52,6 @@ meson compile -C build
 meson test -C build
 ```
 
-
-
 ### MacOS
 
 For MacOS with Apple's Clang and Homebrew GCC,

meson.build

@@ -1,7 +1,7 @@
 project('Fortran_c_cxx_interface', 'c', 'cpp', 'fortran',
 version : '1.3.0',
 meson_version: '>= 0.55.0',
-default_options : ['default_library=static', 'cpp_std=c++11', 'c_std=c99'])
+default_options : ['cpp_std=c++11', 'c_std=c99'])
 
 cpp = meson.get_compiler('cpp')
 cstdlib = cpp.find_library('stdc++', required : true)

src/CMakeLists.txt

@@ -5,11 +5,11 @@ add_subdirectory(cxx)
 add_subdirectory(fortran)
 
 # -- Fortran calling C++
-add_executable(fortran_cxx_math fortran/math_main.f90)
-target_link_libraries(fortran_cxx_math PRIVATE math_cxx)
+add_executable(fortran_cxx_vector fortran/vector_main.f90)
+target_link_libraries(fortran_cxx_vector PRIVATE vector_cxx)
 # LINKER_LANGUAGE option is necessary for ifort at least
-set_target_properties(fortran_cxx_math PROPERTIES LINKER_LANGUAGE Fortran)
-add_test(NAME Fortran_C++_math COMMAND fortran_cxx_math)
+set_target_properties(fortran_cxx_vector PROPERTIES LINKER_LANGUAGE Fortran)
+add_test(NAME Fortran_C++_vector COMMAND fortran_cxx_vector)
 
 add_executable(fortran_cxx_struct fortran/struct_main.f90)
 target_link_libraries(fortran_cxx_struct PRIVATE struct_cxx)
@@ -24,9 +24,9 @@ COMMAND ${CMAKE_COMMAND} -Dexe=$<TARGET_FILE:fortran_cxx_error> -Dexp_code=42 -P
 )
 
 # -- Fortran calling C
-add_executable(fortran_c_math fortran/math_main.f90)
-target_link_libraries(fortran_c_math PRIVATE math_c)
-add_test(NAME Fortran_C_math COMMAND fortran_c_math)
+add_executable(fortran_c_vector fortran/vector_main.f90)
+target_link_libraries(fortran_c_vector PRIVATE vector_c)
+add_test(NAME Fortran_C_vector COMMAND fortran_c_vector)
 
 add_executable(fortran_c_struct fortran/struct_main.f90)
 target_link_libraries(fortran_c_struct PRIVATE struct_c)
@@ -39,6 +39,11 @@ COMMAND ${CMAKE_COMMAND} -Dexe=$<TARGET_FILE:fortran_c_error> -Dexp_code=42 -P $
 )
 
 # -- C calling Fortran
+add_executable(c_fortran_submodule c/submodule_main.c)
+target_link_libraries(c_fortran_submodule PRIVATE submodule_fortran)
+set_target_properties(c_fortran_submodule PROPERTIES LINKER_LANGUAGE C)
+add_test(NAME C_Fortran_submodule COMMAND c_fortran_submodule)
+
 add_executable(c_fortran_error c/error_main.c)
 target_link_libraries(c_fortran_error PRIVATE error_fortran)
 # LINKER_LANGUAGE option is necessary for ifort at least
@@ -54,9 +59,18 @@ target_compile_definitions(c_fortran_struct PRIVATE $<$<BOOL:${MSVC}>:_CRT_SECUR
 add_test(NAME C_Fortran_struct COMMAND c_fortran_struct)
 
 # -- C++ calling Fortran
-add_executable(cxx_call_fortran cxx/math_main.cxx)
-target_link_libraries(cxx_call_fortran PRIVATE math_fortran)
-add_test(NAME C++_Fortran_math COMMAND cxx_call_fortran)
+add_executable(cxx_fortran_submodule cxx/submodule_main.cxx)
+target_link_libraries(cxx_fortran_submodule PRIVATE submodule_fortran)
+target_compile_definitions(cxx_fortran_submodule PRIVATE _USE_MATH_DEFINES)
+add_test(NAME C++_Fortran_submodule COMMAND cxx_fortran_submodule)
+
+add_executable(cxx_fortran_array cxx/array_main.cxx)
+target_link_libraries(cxx_fortran_array PRIVATE vector_fortran)
+add_test(NAME C++_Fortran_array COMMAND cxx_fortran_array)
+
+add_executable(cxx_fortran_vector cxx/vector_main.cxx)
+target_link_libraries(cxx_fortran_vector PRIVATE vector_fortran)
+add_test(NAME C++_Fortran_vector COMMAND cxx_fortran_vector)
 
 add_executable(cxx_fortran_error cxx/error_main.cxx)
 target_link_libraries(cxx_fortran_error PRIVATE error_fortran)
@@ -76,9 +90,9 @@ add_test(NAME C++_Fortran_struct COMMAND cxx_fortran_struct)
 # -- test wrapup
 set_tests_properties(
 C_Fortran_error C_Fortran_struct
-C++_Fortran_math C++_Fortran_error C++_Fortran_struct
-Fortran_C_math Fortran_C_struct
-Fortran_C++_math Fortran_C++_struct
+C++_Fortran_vector C++_Fortran_error C++_Fortran_struct
+Fortran_C_vector Fortran_C_struct
+Fortran_C++_vector Fortran_C++_struct
 PROPERTIES
 TIMEOUT 5
 )

src/c/CMakeLists.txt

@@ -1,4 +1,4 @@
-add_library(math_c OBJECT math_lib.c)
+add_library(vector_c OBJECT vector_lib.c)
 
 add_library(struct_c OBJECT struct_lib.c)
 

src/c/meson.build

@@ -1,4 +1,4 @@
-math_c = library('math_c', 'math_lib.c')
+vector_c = library('vector_c', 'vector_lib.c')
 
 struct_c = library('struct_c', 'struct_lib.c')
 

src/c/submodule_main.c

@@ -0,0 +1,22 @@
+// main C program using a Fortran submodule
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#define _USE_MATH_DEFINES
+#include <math.h>
+
+extern float pi();
+
+int main() {
+
+  if (fabs(pi() - M_PI) > 1e-4) {
+    fprintf(stderr, "pi() unexpected value: %f\n", pi());
+    return EXIT_FAILURE;
+  }
+
+  printf("OK: pi() value: %f\n", pi());
+
+  return EXIT_SUCCESS;
+
+}

src/c/math_lib.c renamed to src/c/vector_lib.c

@@ -1,4 +1,4 @@
-add_library(math_cxx OBJECT math_lib.cxx)
+add_library(vector_cxx OBJECT vector_lib.cxx)
 
 add_library(struct_cxx OBJECT struct_lib.cxx)
 target_include_directories(struct_cxx PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/../c)