bugfix: fix for windows and arm long long int

fixes [#183](#183)

There is an issue when building on mac (arm_64) or windows. The version
of `libtorch` exposes a torch tensors shape (`t->sizes().data()`) as a
`const long long int*` instead of just a `const long int*` like on linux
and mac (x86).

This commit adds preprocessor macro to switch between implementations
automatically detecting the correct version at CMake build stage.

.github/workflows/fypp_checks.yml

@@ -30,9 +30,9 @@ jobs:
 
     - name: Check ftorch.fypp matches ftorch.f90
       run: |
-        fypp src/ftorch.fypp src/temp.f90_temp
-        if ! diff -q src/ftorch.f90 src/temp.f90_temp; then
-          echo "Error: The code in ftorch.f90 does not match that expected from ftorch.fypp."
+        fypp src/ftorch.fypp src/temp.F90_temp
+        if ! diff -q src/ftorch.F90 src/temp.F90_temp; then
+          echo "Error: The code in ftorch.F90 does not match that expected from ftorch.fypp."
           echo "Please re-run fypp on ftorch.fypp to ensure consistency and re-commit."
           exit 1
         else

examples/n_c_and_cpp/CMakeLists.txt

@@ -35,7 +35,7 @@ set(CMAKE_INSTALL_RPATH $ORIGIN/${relDir})
 find_package(Torch REQUIRED)
 
 # Library with C and Fortran bindings
-add_library(${LIB_NAME} SHARED ctorch.cpp ftorch.f90)
+add_library(${LIB_NAME} SHARED ctorch.cpp ftorch.F90)
 add_library(${PROJECT_NAME}::${LIB_NAME} ALIAS ${LIB_NAME})
 set_target_properties(${LIB_NAME} PROPERTIES
   PUBLIC_HEADER "ctorch.h"

src/CMakeLists.txt

@@ -52,7 +52,15 @@ set(CMAKE_INSTALL_RPATH $ORIGIN/${relDir})
 find_package(Torch REQUIRED)
 
 # Library with C and Fortran bindings
-add_library(${LIB_NAME} SHARED ctorch.cpp ftorch.f90 ftorch_test_utils.f90)
+add_library(${LIB_NAME} SHARED ctorch.cpp ftorch.F90 ftorch_test_utils.f90)
+
+if(UNIX)
+  message(STATUS "CMAKE_SYSTEM_PROCESSOR = ${CMAKE_SYSTEM_PROCESSOR}")
+  if(CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64")
+    target_compile_definitions(${LIB_NAME} PRIVATE UNIX)
+  endif()
+endif()
+
 # Add an alias FTorch::ftorch for the library
 add_library(${PROJECT_NAME}::${LIB_NAME} ALIAS ${LIB_NAME})
 set_target_properties(${LIB_NAME} PROPERTIES

src/ctorch.cpp

@@ -224,10 +224,17 @@ int torch_tensor_get_rank(const torch_tensor_t tensor) {
   return t->sizes().size();
 }
 
+#ifdef UNIX
 const long int *torch_tensor_get_sizes(const torch_tensor_t tensor) {
   auto t = reinterpret_cast<torch::Tensor *>(tensor);
   return t->sizes().data();
 }
+#else
+const long long int *torch_tensor_get_sizes(const torch_tensor_t tensor) {
+  auto t = reinterpret_cast<torch::Tensor *>(tensor);
+  return t->sizes().data();
+}
+#endif
 
 void torch_tensor_delete(torch_tensor_t tensor) {
   auto t = reinterpret_cast<torch::Tensor *>(tensor);

src/ctorch.h

@@ -128,7 +128,12 @@ EXPORT_C int torch_tensor_get_rank(const torch_tensor_t tensor);
  * @param Torch Tensor to determine the rank of
  * @return pointer to the sizes array of the Torch Tensor
  */
+#ifdef UNIX
 EXPORT_C const long int *torch_tensor_get_sizes(const torch_tensor_t tensor);
+#else
+EXPORT_C const long long int *
+torch_tensor_get_sizes(const torch_tensor_t tensor);
+#endif
 
 /**
  * Function to delete a Torch Tensor to clean up

src/ftorch.f90 → src/ftorch.F90

@@ -367,9 +367,13 @@ end function get_rank
 
   !> Determines the shape of a tensor.
   function get_shape(self) result(sizes)
-    use, intrinsic :: iso_c_binding, only : c_int, c_long, c_ptr
+    use, intrinsic :: iso_c_binding, only : c_int, c_long, c_long_long, c_ptr
     class(torch_tensor), intent(in) :: self
+#ifdef UNIX
     integer(kind=c_long), pointer :: sizes(:) !! Pointer to tensor data
+#else
+    integer(kind=c_long_long), pointer :: sizes(:) !! Pointer to tensor data
+#endif
     integer(kind=int32) :: ndims(1)
     type(c_ptr) :: cptr
 

src/ftorch.fypp

@@ -334,9 +334,13 @@ contains
 
   !> Determines the shape of a tensor.
   function get_shape(self) result(sizes)
-    use, intrinsic :: iso_c_binding, only : c_int, c_long, c_ptr
+    use, intrinsic :: iso_c_binding, only : c_int, c_long, c_long_long, c_ptr
     class(torch_tensor), intent(in) :: self
+#ifdef UNIX
     integer(kind=c_long), pointer :: sizes(:) !! Pointer to tensor data
+#else
+    integer(kind=c_long_long), pointer :: sizes(:) !! Pointer to tensor data
+#endif
     integer(kind=int32) :: ndims(1)
     type(c_ptr) :: cptr