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| author | Roland McGrath <roland@gnu.org> | 2006-02-22 06:58:11 +0000 |
|---|---|---|
| committer | Roland McGrath <roland@gnu.org> | 2006-02-22 06:58:11 +0000 |
| commit | 11883883a5b9cd7826dfc813a3ec479ead9e4537 (patch) | |
| tree | 053e60e3ef31fa52f7668a13e39dc6bc72a5aa40 /manual/memory.texi | |
| parent | edb72ee4e5cb2c1067102edabe4137d3f960e521 (diff) | |
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[BZ #315]
2004-08-09 Paul Eggert <eggert@cs.ucla.edu>
[BZ #315]
* 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>.
Diffstat (limited to 'manual/memory.texi')
| -rw-r--r-- | manual/memory.texi | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/manual/memory.texi b/manual/memory.texi index 0f28806a22..91b9d84eb2 100644 --- a/manual/memory.texi +++ b/manual/memory.texi @@ -1968,7 +1968,8 @@ obstack_next_free (@var{obstack-ptr}) - obstack_base (@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). |