Respond to PR feedback: Rename some identifiers for clarity

Also add some explanatory comments

Co-authored-by: Katherine Rasmussen <[email protected]>

Author: bonachea

src/caffeine/atomic_s.F90

@@ -10,10 +10,10 @@
   implicit none
 
   ! placeholder variables that simplify the macro logic below
-  integer(PRIF_ATOMIC_INT_KIND) :: dummyti
-  logical(PRIF_ATOMIC_LOGICAL_KIND) :: dummytl
-  integer(PRIF_ATOMIC_INT_KIND), parameter :: dummyvi = 0 
-  logical(PRIF_ATOMIC_LOGICAL_KIND), parameter :: dummyvl = .false. 
+  integer(PRIF_ATOMIC_INT_KIND) :: out_placeholder_int
+  logical(PRIF_ATOMIC_LOGICAL_KIND) :: out_placeholder_logical
+  integer(PRIF_ATOMIC_INT_KIND), parameter :: in_placeholder_int = 0
+  logical(PRIF_ATOMIC_LOGICAL_KIND), parameter :: in_placeholder_logical = .false.
 contains
 
 #define ATOMIC_OP(OPNAME, OPCODE, caf_op) \
@@ -22,10 +22,10 @@
     call_assert(offset >= 0); \
     call base_pointer(coarray_handle, image_num, remote_base); \
     call CAF_CONCAT3(prif_atomic_,OPNAME,_indirect) \
-      ( image_num, remote_base + offset, OPPASSI, stat ); \
+      ( image_num, remote_base + offset, OPPASSF, stat ); \
   end procedure ; \
   module procedure CAF_CONCAT3(prif_atomic_,OPNAME,_indirect) ; \
-    call_assert(c_sizeof(dummyti) == 8); call_assert(c_sizeof(dummytl) == 8); \
+    call_assert(c_sizeof(out_placeholder_int) == 8); call_assert(c_sizeof(out_placeholder_logical) == 8); \
     call_assert_describe(image_num > 0 .and. image_num <= initial_team%num_images, "image_num not within valid range"); \
     call caf_op(CAF_CONCAT2(CAF_OP_,OPCODE), image_num, atom_remote_ptr, OPPASSC); \
     if (present(stat)) stat = 0; \
@@ -35,37 +35,41 @@
 #define ATOMIC_INT_OP(OPNAME,_,OPCODE) ATOMIC_OP(OPNAME,OPCODE,caf_atomic_int)
 #define ATOMIC_LOG_OP(OPNAME,_,OPCODE) ATOMIC_OP(OPNAME,OPCODE,caf_atomic_logical)
 
-#undef  OPPASSI
-#define OPPASSI value
+! OPPASSF defines the dummy argument pass-thru in Fortran,
+! from the direct module procedure to the indirect variant
+#undef  OPPASSF
+#define OPPASSF value
+! OPPASSC defines the dummy argument pass-thru to C,
+! from the indirect module procedure to the BIND(C) call
 #undef  OPPASSC
-#define OPPASSC value, dummyvi, dummyvi
+#define OPPASSC value, in_placeholder_int, in_placeholder_int
   ATOMIC_INT_OP(ref_int,        ,GET)
 #undef  OPPASSC
-#define OPPASSC value, dummyvl, dummyvl
+#define OPPASSC value, in_placeholder_logical, in_placeholder_logical
   ATOMIC_LOG_OP(ref_logical,    ,GET)
 #undef  OPPASSC
-#define OPPASSC dummytl, value, dummyvl
+#define OPPASSC out_placeholder_logical, value, in_placeholder_logical
   ATOMIC_LOG_OP(define_logical, ,SET)
 #undef  OPPASSC
-#define OPPASSC dummyti, value, dummyvi
+#define OPPASSC out_placeholder_int, value, in_placeholder_int
   ATOMIC_INT_OP(define_int,     ,SET)
 
   ATOMIC_INT_OP(add,            ,ADD)
   ATOMIC_INT_OP(and,            ,AND)
   ATOMIC_INT_OP(or,             ,OR)
   ATOMIC_INT_OP(xor,            ,XOR)
 
-#undef  OPPASSI
-#define OPPASSI value, old
+#undef  OPPASSF
+#define OPPASSF value, old
 #undef  OPPASSC
-#define OPPASSC old, value, dummyvi
+#define OPPASSC old, value, in_placeholder_int
   ATOMIC_INT_OP(fetch_add,      ,FADD)
   ATOMIC_INT_OP(fetch_and,      ,FAND)
   ATOMIC_INT_OP(fetch_or,       ,FOR)
   ATOMIC_INT_OP(fetch_xor,      ,FXOR)
 
-#undef  OPPASSI
-#define OPPASSI old, compare, new
+#undef  OPPASSF
+#define OPPASSF old, compare, new
 #undef  OPPASSC
 #define OPPASSC old, compare, new
   ATOMIC_INT_OP(cas_int,        ,FCAS)