[Bug manual/315] New: documentation correction for obstack alignment

["eggert at gnu dot org" <sourceware-bugzilla at sources dot redhat dot com>]

2004-08-09  Paul Eggert  <eggert@cs.ucla.edu>

	* manual/memory.texi (Obstacks Data Alignment): The default
	alignment is not 4: it is enough to hold any type of data.
	Problem reported by Benno in
	<http://sources.redhat.com/ml/libc-alpha/2004-08/msg00055.html>.

--- memory.texi	2003-02-25 02:10:35 -0800
+++ /home/eggert/junk/memory.texi	2004-08-09 21:39:42 -0700
@@ -1968,7 +1968,8 @@ obstack_next_free (@var{obstack-ptr}) - 
 
 Each obstack has an @dfn{alignment boundary}; each object allocated in
 the obstack automatically starts on an address that is a multiple of the
-specified boundary.  By default, this boundary is 4 bytes.
+specified boundary.  By default, this boundary is aligned so that
+the object can hold any type of data.
 
 To access an obstack's alignment boundary, use the macro
 @code{obstack_alignment_mask}, whose function prototype looks like
@@ -1980,7 +1981,9 @@ this:
 The value is a bit mask; a bit that is 1 indicates that the corresponding
 bit in the address of an object should be 0.  The mask value should be one
 less than a power of 2; the effect is that all object addresses are
-multiples of that power of 2.  The default value of the mask is 3, so that
+multiples of that power of 2.  The default value of the mask is a value
+that allows aligned objects to hold any type of data: for example, if
+its value is 3, any type of data can be stored at locations whose
 addresses are multiples of 4.  A mask value of 0 means an object can start
 on any multiple of 1 (that is, no alignment is required).

-- 
           Summary: documentation correction for obstack alignment
           Product: glibc
           Version: 2.3.3
            Status: NEW
          Severity: normal
          Priority: P2
         Component: manual
        AssignedTo: roland at gnu dot org
        ReportedBy: eggert at gnu dot org
                CC: glibc-bugs at sources dot redhat dot com
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://sources.redhat.com/bugzilla/show_bug.cgi?id=315

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