Introduce macros CCTK_DECLARE and CCTK_DECLARE_INIT which declare or

declare and initialise local variables.  They also add the necessary
magic to prevent compiler warnings about unused variables.

If the compiler supports __attribute__((unused)), then use this.
Otherwise, use the existing fallback of taking the variable's
address.  In Fortran, use the variable's kind as fallback.

Use these macros in autogenerated code and in "cctk.h".


git-svn-id: http://svn.cactuscode.org/flesh/trunk@4146 17b73243-c579-4c4c-a9d2-2d5706c11dac

1 files changed, 55 insertions, 1 deletions

diff --git a/src/include/cctk_Types.h b/src/include/cctk_Types.h
index 8405b3f3..1b50fada 100644
--- a/src/include/cctk_Types.h
+++ b/src/include/cctk_Types.h
@@ -21,6 +21,33 @@
 /* Define stuff for C. */
 #ifdef CCODE
 
+
+/* Declare and initialise a variable and tell the compiler that it may
+   be unused.  This is used for CCTK_PARAMETERS and CCTK_ARGUMENTS.
+
+   The macro CCTK_DECLARE_INIT (typ, nam, val) is used with
+   typ: a type, used to declare the variable (e.g. "const int")
+   nam: the variable name (e.g. "x")
+   val: the value used to initialise it (e.g. "42")
+*/
+
+#if    (! __cplusplus && HAVE_CCTK_C_ATTRIBUTE_UNUSED  )  \
+    || (  __cplusplus && HAVE_CCTK_CXX_ATTRIBUTE_UNUSED)
+
+/* We have __attribute__((unused)), so use it */
+#define CCTK_DECLARE_INIT(typ,nam,val)          \
+  typ nam __attribute__((unused)) = (val);
+
+#else
+
+/* Some fallback, bound to fool most compilers */
+#define CCTK_DECLARE_INIT(typ,nam,val)                                  \
+  typ nam = (val);                                                      \
+  void const * cctki_use_##nam = (cctki_use_##nam = &nam, &cctki_use_##nam);
+
+#endif
+
+
 typedef void *CCTK_POINTER;
 typedef const void *CCTK_POINTER_TO_CONST;
 typedef void (*CCTK_FPOINTER)(void);
@@ -63,9 +90,36 @@ typedef unsigned char CCTK_BYTE;
 
 #endif /* CCODE */
 
-/* Define stuff for fortran. */
+/* Define stuff for Fortran. */
 #ifdef FCODE
 
+
+/* Declare a variable and tell the compiler that it may be unused.
+   This is used for CCTK_ARGUMENTS.
+
+   The macro CCTK_DECLARE (typ, nam, dim) is used with
+   typ: a type, used to declare the variable (e.g. "CCTK_REAL")
+   nam: the variable name (e.g. "x")
+   dim: optional array dimensions, (e.g. "(10,10)")
+*/
+
+#ifdef F90CODE
+
+/* Declare it, and use it for a dummy operation  */
+#define CCTK_DECLARE(typ,nam,dim)                       \
+  typ nam dim &&                                        \
+  integer, parameter :: cctki_use_/**/nam = kind(nam)
+
+#else
+
+/* Just declare it; FORTRAN 77 has no good way of marking it as used
+   within a block of declarations  */
+#define CCTK_DECLARE(typ,nam,dim)               \
+  typ nam dim
+
+#endif
+
+
 #define CCTK_POINTER          integer*SIZEOF_CHAR_P
 #define CCTK_POINTER_TO_CONST integer*SIZEOF_CHAR_P
 /* TODO: add autoconf for determining the size of function pointers */