size_t should be 64-bits on a 64-bit machine. mmsize_t should be 32-bits (unless CONFIG_MM_SMALL is selected). This commit backs out the last change to stddef.h

ChangeLog

@@ -11140,3 +11140,9 @@
 	  of the block driver (2015-11-21).
 	* libc/stdio/lib_freopen.c and include/stdio.h:  Add support for
 	  freopen() (2015-11-22).
+	* include/sys/types.h and include/nuttx/mm.h: When building on a 64-bit
+	  machine, the size of size_t should be 64-bits. In general, I believe
+	  that sizeof(size_t) should be the same as sizeof(uinptr_t).  mmsize_t
+	  should always be 32-bits in any event.  The last change to stddef has
+	  been backed out.  With these changes, the simulator builds without
+	  warnings on a 64-bit machine (2015-11-23).

include/nuttx/mm/mm.h

@@ -186,7 +186,7 @@
    typedef uint16_t mmsize_t;
 #  define MMSIZE_MAX 0xffff
 #else
-   typedef size_t mmsize_t;
+   typedef uint32_t mmsize_t;
 #  define MMSIZE_MAX SIZE_MAX
 #endif
 

include/stddef.h

@@ -65,7 +65,7 @@
  * Reference: Opengroup.org
  */
 
-#define offsetof(type, member) ((size_t)(uintptr_t)&(((type *)0)->member))
+#define offsetof(a, b) ((size_t)(&(((a *)(0))->b)))
 
 /****************************************************************************
  * Type Definitions

include/sys/types.h

@@ -142,10 +142,14 @@ typedef int16_t      ssize_t;
 typedef uint16_t     rsize_t;
 
 #else /* CONFIG_SMALL_MEMORY */
+/* As a general rule, the size of size_t should be the same as the size of
+ * uintptr_t: 32-bits on a machine with 32-bit addressing but 64-bits on a
+ * machine with 64-bit addressing.
+ */
 
-typedef uint32_t     size_t;
-typedef int32_t      ssize_t;
-typedef uint32_t     rsize_t;
+typedef uintptr_t    size_t;
+typedef intptr_t     ssize_t;
+typedef uintptr_t    rsize_t;
 
 #endif /* CONFIG_SMALL_MEMORY */