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[svn-r4163] Purpose:

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Fixes bug #503
Description:
    H5Gunlink -- Changed "file space is reclaimed" ot "released".
                 Added note re: freespace and packing.
                 Heavy edit of Purpose and Description.
Platforms tested:
    IE 5
This commit is contained in:
Frank Baker
2001-07-09 16:17:13 -05:00
parent 017b67a742
commit f4da6baf5d
1 changed files with 22 additions and 9 deletions
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31
doc/html/RM_H5G.html
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@@ -347,19 +347,32 @@ create or access function.
<em>const char *</em><code>name</code>
)
<dt><strong>Purpose:</strong>
<dd>Removes the specified <code>name</code> from the group graph and
decrements the link count for the object to which <code>name</code> points
<dd>Removes the link to an object from a group.
<dt><strong>Description:</strong>
<dd><code>H5Gunlink</code> removes an association between a name and an object.
Object headers keep track of how many hard links refer to the object;
when the hard link count reaches zero, the object can be removed
<dd><code>H5Gunlink</code> removes the object specified by
<code>name</code> from the group graph and decrements the
link count for the object to which <code>name</code> points.
This action eliminates any association between <code>name</code>
and the object to which <code>name</code> pointed.
<p>
Object headers keep track of how many hard links refer to an object;
when the link count reaches zero, the object can be removed
from the file. Objects which are open are not removed until all
identifiers to the object are closed.
<p>
If the link count reaches zero, all file-space associated with
the object will be reclaimed. If the object is open, the
reclamation of the file space is delayed until all handles to the
object are closed.
If the link count reaches zero, all file space associated with
the object will be released, i.e., identified in memory as freespace.
If the any object identifier is open for the object, the space
will not be released until after the object identifier is closed.
<p>
<!-- editingcomment: freespace and file packing -->
Note that space identified as freespace is available for re-use
only as long as the file remains open; once a file has been
closed, the HDF5 library loses track of freespace.
Identifying freespace does not imply that the file
will be packed or that, if the file is closed and later reopened,
that the space will be available for re-use.
Such functionality has not yet been implemented in the HDF5 library.
<dt><strong>Warning:</strong>
<dd>Exercise care in unlinking groups as it is possible to render data in
a file inaccessible with <code>H5Gunlink</code>.