Change realloc(foo,0) to behave like malloc(0). Both now return a pointer

to an object of size zero. This will allow testing on reallocs return value
to determine if the operation was successful or not.

src/lib/libc/stdlib/malloc.3

@@ -33,7 +33,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.\"	$OpenBSD: malloc.3,v 1.6 1997/05/31 08:55:05 tholo Exp $
+.\"	$OpenBSD: malloc.3,v 1.7 1997/08/23 10:43:24 pefo Exp $
 .\"
 .Dd August 27, 1996
 .Dt MALLOC 3
@@ -77,6 +77,8 @@ coercion) for storage of any type of object. If the space is of
 .Em pagesize
 or larger, the memory returned will be page-aligned.
 .Pp
+Allocation of a zero size object returns a pointer to a zero size object.
+.Pp
 The
 .Fn free
 function causes the space pointed to by
@@ -120,7 +122,8 @@ If
 .Fa size
 is zero and
 .Fa ptr
-is not a null pointer, the object it points to is freed.
+is not a null pointer, the object it points to is freed and a new zero size
+object is returned.
 .Pp
 Malloc will first look for a symbolic link called
 .Pa /etc/malloc.conf
@@ -211,8 +214,8 @@ function returns no value.
 .Pp
 The
 .Fn realloc
-function returns either a null pointer or a pointer
-to the possibly moved allocated space.
+function a pointer to the possibly moved allocated space;
+otherwise a null pointer is returned.
 .Sh MESSAGES
 If 
 .Fn malloc ,

src/lib/libc/stdlib/malloc.c

@@ -8,7 +8,7 @@
  */
 
 #if defined(LIBC_SCCS) && !defined(lint)
-static char rcsid[] = "$OpenBSD: malloc.c,v 1.28 1997/08/22 17:06:59 deraadt Exp $";
+static char rcsid[] = "$OpenBSD: malloc.c,v 1.29 1997/08/23 10:43:25 pefo Exp $";
 #endif /* LIBC_SCCS and not lint */
 
 /*
@@ -1234,9 +1234,6 @@ realloc(void *ptr, size_t size)
     }
     if (!ptr) {
 	r = imalloc(size);
-    } else if (ptr && !size) {
-	ifree(ptr);
-	r = 0;
     } else {
         r = irealloc(ptr, size);
     }