Use offsetof instead of own definition

* lisp.h: Include <stddef.h>.
(OFFSETOF): Don't define.
(VECSIZE): Use offsetof instead of OFFSETOF.
(PSEUDOVECSIZE): Likewise.
* process.c (conv_sockaddr_to_lisp): Likewise.
* alloc.c: Don't include <stddef.h>.
* buffer.h (PER_BUFFER_VAR_OFFSET): Use offsetof.

src/ChangeLog

@@ -1,5 +1,13 @@
 2010-07-11  Andreas Schwab  <schwab@linux-m68k.org>
 
+	* lisp.h: Include <stddef.h>.
+	(OFFSETOF): Don't define.
+	(VECSIZE): Use offsetof instead of OFFSETOF.
+	(PSEUDOVECSIZE): Likewise.
+	* process.c (conv_sockaddr_to_lisp): Likewise.
+	* alloc.c: Don't include <stddef.h>.
+	* buffer.h (PER_BUFFER_VAR_OFFSET): Use offsetof.
+
 	* process.c: Remove obsolete comment.
 
 2010-07-11  Chong Yidong  <cyd@stupidchicken.com>

src/alloc.c

@@ -23,10 +23,6 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <limits.h>		/* For CHAR_BIT.  */
 #include <setjmp.h>
 
-#ifdef STDC_HEADERS
-#include <stddef.h>		/* For offsetof, used by PSEUDOVECSIZE. */
-#endif
-
 #ifdef ALLOC_DEBUG
 #undef INLINE
 #endif

src/buffer.h

@@ -954,7 +954,7 @@ extern int last_per_buffer_idx;
    from the start of a buffer structure.  */
 
 #define PER_BUFFER_VAR_OFFSET(VAR) \
-  ((char *) &((struct buffer *)0)->VAR - (char *) ((struct buffer *)0))
+  offsetof (struct buffer, VAR)
 
 /* Return the index of buffer-local variable VAR.  Each per-buffer
    variable has an index > 0 associated with it, except when it always

src/lisp.h

@@ -22,6 +22,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #define EMACS_LISP_H
 
 #include <stdarg.h>
+#include <stddef.h>
 
 /* Use the configure flag --enable-checking[=LIST] to enable various
    types of run time checks for Lisp objects.  */
@@ -784,13 +785,6 @@ struct Lisp_String
     unsigned char *data;
   };
 
-#ifdef offsetof
-#define OFFSETOF(type,field) offsetof(type,field)
-#else
-#define OFFSETOF(type,field) \
-  ((int)((char*)&((type*)0)->field - (char*)0))
-#endif
-
 struct Lisp_Vector
   {
     EMACS_UINT size;
@@ -801,7 +795,7 @@ struct Lisp_Vector
 /* If a struct is made to look like a vector, this macro returns the length
    of the shortest vector that would hold that struct.  */
 #define VECSIZE(type) ((sizeof (type)					  \
-			- OFFSETOF (struct Lisp_Vector, contents[0])      \
+			- offsetof (struct Lisp_Vector, contents[0])      \
                         + sizeof(Lisp_Object) - 1) /* round up */	  \
 		       / sizeof (Lisp_Object))
 
@@ -809,7 +803,7 @@ struct Lisp_Vector
    at the end and we need to compute the number of Lisp_Object fields (the
    ones that the GC needs to trace).  */
 #define PSEUDOVECSIZE(type, nonlispfield) \
-  ((OFFSETOF(type, nonlispfield) - OFFSETOF(struct Lisp_Vector, contents[0])) \
+  ((offsetof(type, nonlispfield) - offsetof(struct Lisp_Vector, contents[0])) \
    / sizeof (Lisp_Object))
 
 /* A char-table is a kind of vectorlike, with contents are like a

src/process.c

@@ -2263,7 +2263,7 @@ conv_sockaddr_to_lisp (struct sockaddr *sa, int len)
   /* Workaround for a bug in getsockname on BSD: Names bound to
      sockets in the UNIX domain are inaccessible; getsockname returns
      a zero length name.  */
-  if (len < OFFSETOF (struct sockaddr, sa_family) + sizeof (sa->sa_family))
+  if (len < offsetof (struct sockaddr, sa_family) + sizeof (sa->sa_family))
     return empty_unibyte_string;
 
   switch (sa->sa_family)
@@ -2303,7 +2303,7 @@ conv_sockaddr_to_lisp (struct sockaddr *sa, int len)
       }
 #endif
     default:
-      len -= OFFSETOF (struct sockaddr, sa_family) + sizeof (sa->sa_family);
+      len -= offsetof (struct sockaddr, sa_family) + sizeof (sa->sa_family);
       address = Fcons (make_number (sa->sa_family),
 		       Fmake_vector (make_number (len), Qnil));
       p = XVECTOR (XCDR (address));