best to use struct with C_BOOL mismatch to show problem

Author: scivision

src/bool/bad_bool.f90

@@ -1,31 +1,41 @@
 module bad_bool
 
 use, intrinsic :: iso_c_binding, only : C_INT
+use, intrinsic :: iso_fortran_env, only : error_unit
 
 implicit none
 
+type, bind(C) :: bool_args
+	logical(kind=selected_logical_kind(64)) :: value
+	integer(C_INT) :: dummy
+end type
+
 contains
 
-logical function logical_not(L, dummy) bind(C)
-logical, intent(in), value :: L
-integer(C_INT), intent(in) :: dummy
+logical function logical_not(args) bind(C)
+type(bool_args), intent(in), value :: args
 
-logical_not = .not. L
+logical_not = .not. args%value
 
-print '(/, a, l1, a, l1)', "logical_not(", L, "): ", logical_not
+print '(/, a, l1, a, l1)', "logical_not(", args%value, "): ", logical_not
 
 print '(a16,2x,a,2x,a8,2x,a8)', "storage_size()", "bits", "hex(in)", "hex(out)"
-print '(a16,2x,i3,2x,z8,2x,z8)', "C_BOOL: ", storage_size(L), L, logical_not
+print '(a16,2x,i3,2x,z8,2x,z8)', "C_BOOL: ", storage_size(args%value), args%value, logical_not
 
-if (dummy /= 42_C_INT) error stop "dummy argument should be 42"
+if (args%dummy /= 42_C_INT) then
+    write(error_unit, '(a,i0,a)') "bool_passthru passed dummy argument ", args%dummy, " but expected 42"
+    error stop
+end if
 
 end function logical_not
 
-logical function bool_passthru(L, dummy) bind(C)
-logical, intent(in), value :: L
-integer(C_INT), intent(in) :: dummy
-if (dummy /= 42_C_INT) error stop "dummy argument should be 42"
-bool_passthru = L
+logical function bool_passthru(args) bind(C)
+type(bool_args), intent(in), value :: args
+if (args%dummy /= 42_C_INT) then
+    write(error_unit, '(a,i0,a)') "bool_passthru passed dummy argument ", args%dummy, " but expected 42"
+    error stop
+end if
+bool_passthru = args%value
 end function bool_passthru
 
 

src/bool/logbool.c

@@ -7,26 +7,26 @@
 
 #include "my_bool.h"
 
-bool logical_not(bool a, int* dummy)
+bool logical_not(bool_args args)
 {
-  printf("C boolean sizeof(%d) = %zu\n", a, sizeof(a));
-  if (*dummy != 42) {
-    fprintf(stderr, "ERROR: dummy argument != 42, but %d\n", *dummy);
+  printf("C boolean sizeof(%d) = %zu\n", args.value, sizeof(args.value));
+  if (args.dummy != 42) {
+    fprintf(stderr, "ERROR: dummy argument != 42, but %d\n", args.dummy);
     exit(EXIT_FAILURE);
   }
 
-  return !a;
+  return !args.value;
 }
 
-bool bool_passthru(bool a, int* dummy)
+bool bool_passthru(bool_args args)
 {
-  printf("C boolean sizeof(%d) = %zu\n", a, sizeof(a));
-  if (*dummy != 42) {
-    fprintf(stderr, "ERROR: dummy argument != 42, but %d\n", *dummy);
+  printf("C boolean sizeof(%d) = %zu\n", args.value, sizeof(args.value));
+  if (args.dummy != 42) {
+    fprintf(stderr, "ERROR: dummy argument != 42, but %d\n", args.dummy);
     exit(EXIT_FAILURE);
   }
 
-  return a;
+  return args.value;
 }
 
 bool bool_true(){ return true; }

src/bool/logbool.cpp

@@ -3,26 +3,26 @@
 
 #include "my_bool.h"
 
-bool logical_not(const bool a, int* dummy)
+bool logical_not(const bool_args args)
 {
-  std::cout << "C++ boolean sizeof(" << a << ") = " << sizeof(a) << "\n";
-  if (*dummy != 42) {
-    std::cerr << "ERROR: dummy argument != 42, but " << *dummy << "\n";
+  std::cout << "C++ boolean sizeof(" << args.value << ") = " << sizeof(args.value) << "\n";
+  if (args.dummy != 42) {
+    std::cerr << "ERROR: dummy argument != 42, but " << args.dummy << "\n";
     std::exit(EXIT_FAILURE);
   }
 
-  return !a;
+  return !args.value;
 }
 
-bool bool_passthru(const bool a, int* dummy)
+bool bool_passthru(const bool_args args)
 {
-  std::cout << "C++ boolean sizeof(" << a << ") = " << sizeof(a) << "\n";
-  if (*dummy != 42) {
-    std::cerr << "ERROR: dummy argument != 42, but " << *dummy << "\n";
+  std::cout << "C++ boolean sizeof(" << args.value << ") = " << sizeof(args.value) << "\n";
+  if (args.dummy != 42) {
+    std::cerr << "ERROR: dummy argument != 42, but " << args.dummy << "\n";
     std::exit(EXIT_FAILURE);
   }
 
-  return a;
+  return args.value;
 }
 
 bool bool_true(){ return true; }

src/bool/logbool.f90

@@ -1,34 +1,42 @@
 module logbool
 
-use, intrinsic :: iso_c_binding, only : C_BOOL, C_INT
+use, intrinsic :: iso_c_binding
+use, intrinsic :: iso_fortran_env
 
 implicit none
 
-contains
+type, bind(C) :: bool_args
+	logical(C_BOOL) :: value
+	integer(C_INT) :: dummy
+end type
 
-logical(c_bool) function logical_not(L, dummy) bind(C)
+contains
 
-logical(c_bool), intent(in), value :: L
-integer(c_int), intent(in) :: dummy
+logical(C_BOOL) function logical_not(args) bind(C)
+type(bool_args), intent(in), value :: args
 
-logical_not = .not. L
+logical_not = .not. args%value
 
-print '(/, a, l1, a, l1)', "logical_not(", L, "): ", logical_not
+print '(/, a, l1, a, l1)', "logical_not(", args%value, "): ", logical_not
 
 print '(a16,2x,a,2x,a8,2x,a8)', "storage_size()", "bits", "hex(in)", "hex(out)"
-print '(a16,2x,i3,2x,z8,2x,z8)', "C_BOOL: ", storage_size(L), L, logical_not
+print '(a16,2x,i3,2x,z8,2x,z8)', "C_BOOL: ", storage_size(args%value), args%value, logical_not
 
-if (dummy /= 42_c_int) error stop "dummy argument should be 42"
-! print '(a)', "logical_not passed dummy argument correctly"
+if (args%dummy /= 42_C_INT) then
+    write(error_unit, '(a,i0,a)') "bool_passthru passed dummy argument ", args%dummy, " but expected 42"
+    error stop
+end if
 
 end function logical_not
 
 
-logical(C_BOOL) function bool_passthru(L, dummy) bind(C)
-logical(C_BOOL), intent(in), value :: L
-integer(C_INT), intent(in) :: dummy
-if (dummy /= 42_C_INT) error stop "dummy argument should be 42"
-bool_passthru = L
+logical(C_BOOL) function bool_passthru(args) bind(C)
+type(bool_args), intent(in), value :: args
+if (args%dummy /= 42_C_INT) then
+    write(error_unit, '(a,i0,a)') "bool_passthru passed dummy argument ", args%dummy, " but expected 42"
+    error stop
+end if
+bool_passthru = args%value
 end function bool_passthru
 
 
@@ -40,4 +48,4 @@ logical(C_BOOL) function bool_false() bind(C)
 bool_false = .false._C_BOOL
 end function
 
-end module logbool
+end module

src/bool/my_bool.h

@@ -2,8 +2,13 @@
 extern "C" {
 #endif
 
-bool logical_not(const bool, int*);
-bool bool_passthru(const bool, int*);
+typedef struct bool_args {
+	bool value;
+	int dummy;
+} bool_args;
+
+bool logical_not(bool_args);
+bool bool_passthru(bool_args);
 
 bool bool_true();
 bool bool_false();

test/bool/main.c

@@ -24,16 +24,16 @@ if(b){
   c++;
 }
 
-// pass a pointer to int with value 42 to check that the Fortran function receives it correctly
-int dummy = 42;
+bool_args args = { true, 42 };
 
-b = logical_not(true, &dummy);
+b = logical_not(args);
 if(b) {
   fprintf(stderr, "logical_not(true) should be false: %d\n", b);
   c++;
 }
 
-b = logical_not(false, &dummy);
+args.value = false;
+b = logical_not(args);
 if (!b) {
   fprintf(stderr, "logical_not(false) should be true: %d\n", b);
   c++;

test/bool/main.cpp

@@ -21,30 +21,31 @@ if(b){
   c++;
 }
 
-// pass a pointer to int with value 42 to check that the Fortran function receives it correctly
-int dummy = 42;
+bool_args args{true, 42};
 
-b = logical_not(true, &dummy);
+b = logical_not(args);
 
 if(b){
   std::cerr << "logical_not(true) failed: " << b << "\n";
   c++;
 }
 
-b = logical_not(false, &dummy);
+args.value = false;
+b = logical_not(args);
 
 if (!b){
   std::cerr << "logical_not(false) failed: " << b << "\n";
   c++;
 }
 
-b = bool_passthru(false, &dummy);
+b = bool_passthru(args);
 if(b){
   std::cerr << "bool_passthru(false) failed: " << b << "\n";
   c++;
 }
 
-b = bool_passthru(true, &dummy);
+args.value = true;
+b = bool_passthru(args);
 if(!b){
   std::cerr << "bool_passthru(true) failed: " << b << "\n";
   c++;