* lib/chown.c (rpl_chown): Return -1 on failure.

[gnulib.git] / lib / intprops.h

diff --git a/lib/intprops.h b/lib/intprops.h
index cd1c172..65280b1 100644 (file)
--- a/lib/intprops.h
+++ b/lib/intprops.h
@@ -14,7 +14,7 @@
 
    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software Foundation,
-   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
 
 /* Written by Paul Eggert.  */
 
@@ -27,29 +27,39 @@
    an integer.  */
 #define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
 
-/* True if negative values of the integer type T use twos complement
-   representation.  */
-#define TYPE_TWOS_COMPLEMENT(t) ((t) - (t) 1 == (t) ((t) ~ (t) 1 + (t) 1))
+/* True if negative values of the signed integer type T use two's
+   complement, ones' complement, or signed magnitude representation,
+   respectively.  Much GNU code assumes two's complement, but some
+   people like to be portable to all possible C hosts.  */
+#define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)
+#define TYPE_ONES_COMPLEMENT(t) ((t) ~ (t) 0 == 0)
+#define TYPE_SIGNED_MAGNITUDE(t) ((t) ~ (t) 0 < (t) -1)
 
 /* True if the arithmetic type T is signed.  */
 #define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
 
 /* The maximum and minimum values for the integer type T.  These
-   macros have undefined behavior if T is signed and has padding bits
-   (i.e., bits that do not contribute to the value), or if T uses
-   signed-magnitude representation.  If this is a problem for you,
-   please let us know how to fix it for your host.  */
-#define TYPE_MINIMUM(t) ((t) (TYPE_SIGNED (t) \
-                             ? ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1) : (t) 0))
-#define TYPE_MAXIMUM(t) ((t) (~ (t) 0 - TYPE_MINIMUM (t)))
-
-/* Bound on length of the string representing an integer value or type T.
+   macros have undefined behavior if T is signed and has padding bits.
+   If this is a problem for you, please let us know how to fix it for
+   your host.  */
+#define TYPE_MINIMUM(t) \
+  ((t) (! TYPE_SIGNED (t) \
+       ? (t) 0 \
+       : TYPE_SIGNED_MAGNITUDE (t) \
+       ? ~ (t) 0 \
+       : ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1)))
+#define TYPE_MAXIMUM(t) \
+  ((t) (! TYPE_SIGNED (t) \
+       ? (t) -1 \
+       : ~ (~ (t) 0 << (sizeof (t) * CHAR_BIT - 1))))
+
+/* Bound on length of the string representing an integer type or expression T.
    Subtract 1 for the sign bit if t is signed; log10 (2.0) < 146/485;
    add 1 for integer division truncation; add 1 more for a minus sign
    if needed.  */
 #define INT_STRLEN_BOUND(t) \
   ((sizeof (t) * CHAR_BIT - 1) * 146 / 485 + 2)
 
-/* Bound on buffer size needed to represent an integer value or type T,
+/* Bound on buffer size needed to represent an integer type or expression T,
    including the terminating null.  */
 #define INT_BUFSIZE_BOUND(t) (INT_STRLEN_BOUND (t) + 1)