mirror of
https://github.com/HDFGroup/hdf5.git
synced 2024-12-09 07:32:32 +08:00
09855e5628
Purpose:
Elaboration on a struct field
Description:
H5Gget_objinfo: Added caveats regarding 'fileno' field in
H5G_stat_t struct.
Platforms tested:
IE 5
846 lines
34 KiB
HTML
846 lines
34 KiB
HTML
<html>
|
|
<head><title>
|
|
HDF5/H5G API Specification
|
|
</title></head>
|
|
|
|
<body bgcolor="#FFFFFF">
|
|
|
|
|
|
<hr>
|
|
<center>
|
|
<table border=0 width=98%>
|
|
<tr><td valign=top align=left>
|
|
<a href="H5.intro.html">Introduction to HDF5</a> <br>
|
|
<a href="H5.user.html">HDF5 User Guide</a> <br>
|
|
<a href="index.html">Other HDF5 documents and links</a> <br>
|
|
<!--
|
|
<a href="Glossary.html">Glossary</a><br>
|
|
-->
|
|
</td>
|
|
<td valign=top align=right>
|
|
And in this document, the
|
|
<a href="RM_H5Front.html">HDF5 Reference Manual</a>
|
|
<br>
|
|
<a href="RM_H5.html">H5</a>
|
|
<a href="RM_H5A.html">H5A</a>
|
|
<a href="RM_H5D.html">H5D</a>
|
|
<a href="RM_H5E.html">H5E</a>
|
|
<a href="RM_H5F.html">H5F</a>
|
|
H5G
|
|
<a href="RM_H5I.html">H5I</a>
|
|
<a href="RM_H5P.html">H5P</a>
|
|
<br>
|
|
<a href="RM_H5R.html">H5R</a>
|
|
<a href="RM_H5S.html">H5S</a>
|
|
<a href="RM_H5T.html">H5T</a>
|
|
<a href="RM_H5Z.html">H5Z</a>
|
|
<a href="Tools.html">Tools</a>
|
|
<a href="PredefDTypes.html">Datatypes</a>
|
|
</td></tr>
|
|
</table>
|
|
</center>
|
|
<hr>
|
|
|
|
|
|
<center>
|
|
<h1>H5G: Group Interface</h1>
|
|
</center>
|
|
|
|
<h2>Group Object API Functions</h2>
|
|
|
|
The Group interface functions create and manipulate groups
|
|
of objects in an HDF5 file.
|
|
<p>
|
|
<strong>The C Interfaces:</strong>
|
|
|
|
<table border=0>
|
|
<tr><td valign=top>
|
|
<ul>
|
|
<li><a href="#Group-Create">H5Gcreate</a>
|
|
<li><a href="#Group-Open">H5Gopen</a>
|
|
<li><a href="#Group-Close">H5Gclose</a>
|
|
</ul>
|
|
</td><td> </td><td valign=top>
|
|
<ul>
|
|
<li><a href="#Group-Link">H5Glink</a>
|
|
<li><a href="#Group-Unlink">H5Gunlink</a>
|
|
<li><a href="#Group-Iterate">H5Giterate</a>
|
|
<li><a href="#Group-Move">H5Gmove</a>
|
|
</ul>
|
|
</td><td> </td><td valign=top>
|
|
<ul>
|
|
<li><a href="#Group-GetObjinfo">H5Gget_objinfo</a>
|
|
<li><a href="#Group-GetLinkval">H5Gget_linkval</a>
|
|
<li><a href="#Group-SetComment">H5Gset_comment</a>
|
|
<li><a href="#Group-GetComment">H5Gget_comment</a>
|
|
</ul>
|
|
</td></tr>
|
|
</table>
|
|
|
|
<p>
|
|
<strong>The FORTRAN90 Interfaces:</strong>
|
|
|
|
<br>
|
|
<font size=-1>
|
|
<i>In general, each FORTRAN90 subroutine performs exactly the same task
|
|
as the corresponding C function. The links below go to the C function
|
|
descriptions, which serve as general descriptions for both. A button,
|
|
under <strong>Non-C API(s)</strong> at the end of the C function description,
|
|
opens an external browser window displaying the FORTRAN90-specific
|
|
information. You will probably want to adjust the size and location of
|
|
this external window so that both browser windows are visible and to
|
|
facilitate moving easily between them.</i>
|
|
</font>
|
|
|
|
<table border=0>
|
|
<tr><td valign=top>
|
|
<ul>
|
|
<li><a href="#Group-Create">h5gcreate_f</a>
|
|
<li><a href="#Group-Open">h5gopen_f</a>
|
|
<li><a href="#Group-Close">h5gclose_f</a>
|
|
<!--<li><a href="#Group-Link">h5glink_f</a>
|
|
-->
|
|
</ul>
|
|
</td><td> </td><td valign=top>
|
|
<ul>
|
|
<li><a href="#Group-Unlink">h5gunlink_f</a>
|
|
<li><a href="#Group-Iterate">h5gget_obj_info_idx_f</a>
|
|
<li><a href="#Group-Iterate">h5gn_members_f</a>
|
|
<li><a href="#Group-Move">h5gmove_f</a>
|
|
</ul>
|
|
</td><td> </td><td valign=top>
|
|
<ul>
|
|
<!--<li><a href="#Group-GetObjinfo">h5gget_objinfo_f</a>
|
|
-->
|
|
<li><a href="#Group-GetLinkval">h5gget_linkval_f</a>
|
|
<li><a href="#Group-SetComment">h5gset_comment_f</a>
|
|
<li><a href="#Group-GetComment">h5gget_comment_f</a>
|
|
</ul>
|
|
</td></tr>
|
|
</table>
|
|
|
|
<p>
|
|
A group associates names with objects and provides a mechanism
|
|
for mapping a name to an object. Since all objects appear in at
|
|
least one group (with the possible exception of the root object)
|
|
and since objects can have names in more than one group, the set
|
|
of all objects in an HDF5 file is a directed graph. The internal
|
|
nodes (nodes with out-degree greater than zero) must be groups
|
|
while the leaf nodes (nodes with out-degree zero) are either empty
|
|
groups or objects of some other type. Exactly one object in every
|
|
non-empty file is the root object. The root object always has a
|
|
positive in-degree because it is pointed to by the file super block.
|
|
|
|
<p>
|
|
An object name consists of one or more components separated from
|
|
one another by slashes. An absolute name begins with a slash and the
|
|
object is located by looking for the first component in the root
|
|
object, then looking for the second component in the first object, etc.,
|
|
until the entire name is traversed. A relative name does not begin
|
|
with a slash and the traversal begins at the location specified by the
|
|
create or access function.
|
|
|
|
<p>
|
|
|
|
|
|
<hr>
|
|
<dl>
|
|
<dt><strong>Name:</strong> <a name="Group-Create">H5Gcreate</a>
|
|
<dt><strong>Signature:</strong>
|
|
<dd><em>hid_t </em><code>H5Gcreate</code>(<em>hid_t</em> <code>loc_id</code>,
|
|
<em>const char *</em><code>name</code>,
|
|
<em>size_t</em> <code>size_hint</code>
|
|
)
|
|
<dt><strong>Purpose:</strong>
|
|
<dd>Creates a new empty group and gives it a name.
|
|
<dt><strong>Description:</strong>
|
|
<dd><code>H5Gcreate</code> creates a new group with the specified
|
|
name at the specified location, <code>loc_id</code>.
|
|
The location is identified by a file or group identifier.
|
|
The name, <code>name</code>, must not already be taken by some
|
|
other object and all parent groups must already exist.
|
|
<p>
|
|
<code>size_hint</code> is a hint for the number of bytes to
|
|
reserve to store the names which will be eventually added to
|
|
the new group. Passing a value of zero for <code>size_hint</code>
|
|
is usually adequate since the library is able to dynamically
|
|
resize the name heap, but a correct hint may result in better
|
|
performance.
|
|
If a non-positive value is supplied for <code>size_hint</code>,
|
|
then a default size is chosen.
|
|
<p>
|
|
The return value is a group identifier for the open group.
|
|
This group identifier should be closed by calling
|
|
<code>H5Gclose</code> when it is no longer needed.
|
|
<dt><strong>Parameters:</strong>
|
|
<dl>
|
|
<dt><em>hid_t</em> <code>loc_id</code>
|
|
<dd>IN: File or group identifier.
|
|
<dt><em>const char *</em><code>name</code>
|
|
<dd>IN: Absolute or relative name of the new group.
|
|
<dt><em>size_t</em> <code>size_hint</code>
|
|
<dd>IN: Optional parameter indicating the number of bytes
|
|
to reserve for the names that will appear in the group.
|
|
A conservative estimate could result in multiple
|
|
system-level I/O requests to read the group name heap;
|
|
a liberal estimate could result in a single large
|
|
I/O request even when the group has just a few names.
|
|
HDF5 stores each name with a null terminator.
|
|
</dl>
|
|
<dt><strong>Returns:</strong>
|
|
<dd>Returns a valid group identifier for the open group if successful;
|
|
otherwise returns a negative value.
|
|
<dt><strong>Non-C API(s):</strong>
|
|
<!--
|
|
<dd><a href="fortran/h5g_FORTRAN.html#h5gcreate_f" target="FortWin" onClick="window.open("fortran/h5g_FORTRAN.html#h5gcreate_f","FortWin","toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=yes,resizable=1,width=500,height=250,titlebar=yes")"><img src="Graphics/FORTRAN.gif"></a>
|
|
-->
|
|
<dd><a href="fortran/h5g_FORTRAN.html#h5gcreate_f"
|
|
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
|
|
<!--
|
|
<img src="Graphics/Java.gif">
|
|
<img src="Graphics/C++.gif">
|
|
-->
|
|
</dl>
|
|
|
|
|
|
|
|
<hr>
|
|
<dl>
|
|
<dt><strong>Name:</strong> <a name="Group-Open">H5Gopen</a>
|
|
<dt><strong>Signature:</strong>
|
|
<dd><em>hid_t </em><code>H5Gopen</code>(<em>hid_t</em> <code>loc_id</code>,
|
|
<em>const char *</em><code>name</code>
|
|
)
|
|
<dt><strong>Purpose:</strong>
|
|
<dd>Opens an existing group for modification and returns a group
|
|
identifier for that group.
|
|
<dt><strong>Description:</strong>
|
|
<dd><code>H5Gopen</code> opens an existing group with the specified
|
|
name at the specified location, <code>loc_id</code>.
|
|
<p>
|
|
The location is identified by a file or group identifier
|
|
<p>
|
|
<code>H5Gopen</code> returns a group identifier for the group
|
|
that was opened. This group identifier should be released by
|
|
calling <code>H5Gclose</code> when it is no longer needed.
|
|
<dt><strong>Parameters:</strong>
|
|
<dl>
|
|
<dt><em>hid_t</em> <code>loc_id</code>
|
|
<dd>IN: File or group identifier within which group is to be open.
|
|
<dt><em>const char *</em> <code>name</code>
|
|
<dd>IN: Name of group to open.
|
|
</dl>
|
|
<dt><strong>Returns:</strong>
|
|
<dd>Returns a valid group identifier if successful;
|
|
otherwise returns a negative value.
|
|
<dt><strong>Non-C API(s):</strong>
|
|
<!--
|
|
<dd><a href="fortran/h5g_FORTRAN.html#h5gopen_f" target="FortWin" onClick="window.open("fortran/h5g_FORTRAN.html#h5gopen_f","FortWin&nquot;,"toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=yes,resizable=1,width=500,height=250,titlebar=yes")"><img src="Graphics/FORTRAN.gif"></a>
|
|
-->
|
|
<dd><a href="fortran/h5g_FORTRAN.html#h5gopen_f"
|
|
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
|
|
<!--
|
|
<img src="Graphics/Java.gif">
|
|
<img src="Graphics/C++.gif">
|
|
-->
|
|
</dl>
|
|
|
|
|
|
<hr>
|
|
<dl>
|
|
<dt><strong>Name:</strong> <a name="Group-Close">H5Gclose</a>
|
|
<dt><strong>Signature:</strong>
|
|
<dd><em>herr_t </em><code>H5Gclose</code>(<em>hid_t </em><code>group_id</code>)
|
|
<dt><strong>Purpose:</strong>
|
|
<dd>Closes the specified group.
|
|
<dt><strong>Description:</strong>
|
|
<dd><code>H5Gclose</code> releases resources used by a group which was
|
|
opened by <code>H5Gcreate</code> or <code>H5Gopen</code>.
|
|
After closing a group, the <code>group_id</code> cannot be used again.
|
|
<p>
|
|
Failure to release a group with this call will result in resource leaks.
|
|
<dt><strong>Parameters:</strong>
|
|
<dl>
|
|
<dt><em>hid_t</em> <code>group_id</code>
|
|
<dd>IN: Group identifier to release.
|
|
</dl>
|
|
<dt><strong>Returns:</strong>
|
|
<dd>Returns a non-negative value if successful;
|
|
otherwise returns a negative value.
|
|
<dt><strong>Non-C API(s):</strong>
|
|
<!--
|
|
<dd><a href="fortran/h5g_FORTRAN.html#h5gclose_f" target="FortWin" onClick="window.open("fortran/h5g_FORTRAN.html#h5gclose_f","FortWin&nquot;,"toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=yes,resizable=1,width=500,height=250,titlebar=yes")"><img src="Graphics/FORTRAN.gif"></a>
|
|
-->
|
|
<dd><a href="fortran/h5g_FORTRAN.html#h5gclose_f"
|
|
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
|
|
<!--
|
|
<img src="Graphics/Java.gif">
|
|
<img src="Graphics/C++.gif">
|
|
-->
|
|
</dl>
|
|
|
|
|
|
<hr>
|
|
<dl>
|
|
<dt><strong>Name:</strong> <a name="Group-Link">H5Glink</a>
|
|
<dt><strong>Signature:</strong>
|
|
<dd><em>herr_t</em> <code>H5Glink</code>(<em>hid_t</em> <code>loc_id</code>,
|
|
<em>H5G_link_t</em> <code>link_type</code>,
|
|
<em>const char *</em><code>current_name</code>,
|
|
<em>const char *</em><code>new_name</code>
|
|
)
|
|
<dt><strong>Purpose:</strong>
|
|
<dd>Creates a link of the specified type from <code>new_name</code>
|
|
to <code>current_name</code>.
|
|
<dt><strong>Description:</strong>
|
|
<dd><code>H5Glink</code> creates a new name for an object that has some current
|
|
name, possibly one of many names it currently has.
|
|
<p>
|
|
If <code>link_type</code> is <code>H5G_LINK_HARD</code>, then
|
|
<code>current_name</code> must specify the name of an
|
|
existing object and both
|
|
names are interpreted relative to <code>loc_id</code>, which is
|
|
either a file identifier or a group identifier.
|
|
<p>
|
|
If <code>link_type</code> is <code>H5G_LINK_SOFT</code>, then
|
|
<code>current_name</code> can be anything and is interpreted at
|
|
lookup time relative to the group which contains the final
|
|
component of <code>new_name</code>. For instance, if
|
|
<code>current_name</code> is <code>./foo</code>,
|
|
<code>new_name</code> is <code>./x/y/bar</code>, and a request
|
|
is made for <code>./x/y/bar</code>, then the actual object looked
|
|
up is <code>./x/y/./foo</code>.
|
|
<dt><strong>Parameters:</strong>
|
|
<dl>
|
|
<dt><em>hid_t</em> <code>loc_id</code>
|
|
<dd>IN: File or group identifier.
|
|
<dt><em>H5G_link_t</em> <code>link_type</code>
|
|
<dd>IN: Link type.
|
|
Possible values are <code>H5G_LINK_HARD</code> and
|
|
<code>H5G_LINK_SOFT</code>.
|
|
<dt><em>const char *</em> <code>current_name</code>
|
|
<dd>IN: Name of the existing object if link is a hard link.
|
|
Can be anything for the soft link.
|
|
<dt><em>const char *</em> <code>new_name</code>
|
|
<dd>IN: New name for the object.
|
|
</dl>
|
|
<dt><strong>Returns:</strong>
|
|
<dd>Returns a non-negative value if successful;
|
|
otherwise returns a negative value.
|
|
<dt><strong>Non-C API(s):</strong>
|
|
<!--
|
|
<dd><a href="fortran/h5g_FORTRAN.html#h5glink_f" target="FortWin" onClick="window.open("fortran/h5g_FORTRAN.html#h5glink_f","FortWin&nquot;,"toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=yes,resizable=1,width=500,height=250,titlebar=yes")"><img src="Graphics/FORTRAN.gif"></a>
|
|
-->
|
|
<dd><a href="fortran/h5g_FORTRAN.html#h5glink_f"
|
|
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
|
|
<!--
|
|
<img src="Graphics/Java.gif">
|
|
<img src="Graphics/C++.gif">
|
|
-->
|
|
</dl>
|
|
|
|
|
|
<hr>
|
|
<dl>
|
|
<dt><strong>Name:</strong> <a name="Group-Unlink">H5Gunlink</a>
|
|
<dt><strong>Signature:</strong>
|
|
<dd><em>herr_t </em><code>H5Gunlink</code>(<em>hid_t</em> <code>loc_id</code>,
|
|
<em>const char *</em><code>name</code>
|
|
)
|
|
<dt><strong>Purpose:</strong>
|
|
<dd>Removes the link to an object from a group.
|
|
<dt><strong>Description:</strong>
|
|
<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 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>
|
|
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. See
|
|
“<a href="Performance.html#Freespace">Freespace Management</a>”
|
|
in the <cite>HDF5 User's Guide</cite> for further details.
|
|
<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>.
|
|
See <a href="Groups.html#H5GUnlinkToCorrupt">The Group Interface</a>
|
|
in the <cite>HDF5 User's Guide</cite>.
|
|
<dt><strong>Parameters:</strong>
|
|
<dl>
|
|
<dt><em>hid_t</em> <code>loc_id</code>
|
|
<dd>IN: Identifier of the file or group containing the object.
|
|
<dt><em>const char *</em> <code>name</code>
|
|
<dd>IN: Name of the object to unlink.
|
|
</dl>
|
|
<dt><strong>Returns:</strong>
|
|
<dd>Returns a non-negative value if successful;
|
|
otherwise returns a negative value.
|
|
<dt><strong>Non-C API(s):</strong>
|
|
<dd><a href="fortran/h5g_FORTRAN.html#h5gunlink_f"
|
|
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
|
|
<!--
|
|
<img src="Graphics/Java.gif">
|
|
<img src="Graphics/C++.gif">
|
|
-->
|
|
</dl>
|
|
|
|
|
|
<hr>
|
|
<dl>
|
|
<dt><strong>Name:</strong> <a name="Group-Iterate">H5Giterate</a>
|
|
<dt><strong>Signature:</strong>
|
|
<dd><em>int</em> <code>H5Giterate</code>(<em>hid_t</em> <code>loc_id</code>,
|
|
<em>const char</em> <code>*name</code>,
|
|
<em>int</em> <code>*idx</code>,
|
|
<em>H5G_iterate_t</em> <code>operator</code>,
|
|
<em>void</em> <code>*operator_data</code>
|
|
)
|
|
<dt><strong>Purpose:</strong>
|
|
<dd>Iterates an operation over the entries of a group.
|
|
<dt><strong>Description:</strong>
|
|
<dd><code>H5Giterate</code> iterates over the members of
|
|
<code>name</code> in the file or group specified with
|
|
<code>loc_id</code>.
|
|
For each object in the group, the <code>operator_data</code>
|
|
and some additional information, specified below, are
|
|
passed to the <code>operator</code> function.
|
|
The iteration begins with the <code>idx</code> object in the
|
|
group and the next element to be processed by the operator is
|
|
returned in <code>idx</code>. If <code>idx</code>
|
|
is NULL, then the iterator starts at the first group member;
|
|
since no stopping point is returned in this case, the iterator
|
|
cannot be restarted if one of the calls to its operator returns
|
|
non-zero.
|
|
<p>
|
|
The prototype for <code>H5G_iterate_t</code> is:
|
|
<ul><dl>
|
|
<dd><code>typedef</code> <em>herr_t </em>(*<code>H5G_iterate_t</code>)(<em>hid_t</em> <code>group_id</code>,
|
|
<em>const char *</em><code>member_name</code>,
|
|
<em>void *</em><code>operator_data</code>);
|
|
</dl></ul>
|
|
<dd>The operation receives the group identifier for the group being
|
|
iterated over, <code>group_id</code>, the name of the current
|
|
object within the group, <code>member_name</code>, and the
|
|
pointer to the operator data passed in to <code>H5Giterate</code>,
|
|
<code>operator_data</code>.
|
|
<p>
|
|
The return values from an operator are:
|
|
<ul>
|
|
<li>Zero causes the iterator to continue, returning
|
|
zero when all group members have been processed.
|
|
<li>Positive causes the iterator to immediately return that positive
|
|
value, indicating short-circuit success. The iterator can be
|
|
restarted at the next group member.
|
|
<li>Negative causes the iterator to immediately return that value,
|
|
indicating failure. The iterator can be restarted at the next
|
|
group member.
|
|
</ul>
|
|
<p>
|
|
<code>H5Giterate</code> assumes that the membership of the group
|
|
identified by <code>name</code> remains unchanged through the
|
|
iteration. If the membership changes during the iteration,
|
|
the function's behavior is undefined.
|
|
<dt><strong>Parameters:</strong>
|
|
<dl>
|
|
<dt><em>hid_t</em> <code>loc_id</code>
|
|
<dd>IN: File or group identifier.
|
|
<dt><em>const char</em> <code>*name</code>
|
|
<dd>IN: Group over which the iteration is performed.
|
|
<dt><em>int</em> <code>*idx</code>
|
|
<dd>IN/OUT: Location at which to begin the iteration.
|
|
<dt><em>H5G_iterate_t</em> <code>operator</code>
|
|
<dd>IN: Operation to be performed on an object at each step of
|
|
the iteration.
|
|
<dt><em>void</em> <code>*operator_data</code>
|
|
<dd>IN/OUT: Data associated with the operation.
|
|
</dl>
|
|
<dt><strong>Returns:</strong>
|
|
<dd>Returns the return value of the last operator if it was non-zero,
|
|
or zero if all group members were processed.
|
|
Otherwise returns a negative value.
|
|
<dt><strong>Non-C API(s):</strong>
|
|
<dd>There is no direct FORTRAN couterpart for the C function
|
|
<code>H5Giterate</code>.
|
|
Instead, that functionality is provided by two FORTRAN functions:
|
|
<center>
|
|
<table width=80%>
|
|
<tr valign=top align=left>
|
|
<td>
|
|
<a href="fortran/h5g_FORTRAN.html#h5gn_members_f"
|
|
target="FortranWin"><code>h5gn_members_f</code></a>.
|
|
</td><td> </td><td>
|
|
<strong>Purpose:</strong>
|
|
Returns the number of group members.
|
|
</tr><tr valign=top align=left>
|
|
<td>
|
|
<a href="fortran/h5g_FORTRAN.html#h5gget_obj_info_idx_f"
|
|
target="FortranWin"><code>h5gget_obj_info_idx_f</code></a>
|
|
</td><td> </td><td>
|
|
<strong>Purpose:</strong>
|
|
Returns name and type of the group member identified by its index.
|
|
</td>
|
|
</table>
|
|
</center>
|
|
<dd><a href="fortran/h5g_FORTRAN.html#h5gn_members_f"
|
|
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
|
|
<!--
|
|
<img src="Graphics/Java.gif">
|
|
<img src="Graphics/C++.gif">
|
|
-->
|
|
</dl>
|
|
|
|
|
|
<hr>
|
|
<dl>
|
|
<dt><strong>Name:</strong> <a name="Group-Move">H5Gmove</a>
|
|
<dt><strong>Signature:</strong>
|
|
<dd><em>herr_t</em> <code>H5Gmove</code>(<em>hid_t</em> <code>loc_id</code>,
|
|
<em>const char</em> <code>*src</code>,
|
|
<em>const char</em> <code>*dst</code>
|
|
)
|
|
<dt><strong>Purpose:</strong>
|
|
<dd>Renames an object within an HDF5 file.
|
|
<dt><strong>Description:</strong>
|
|
<dd><code>H5Gmove</code> renames an object within an HDF5 file.
|
|
The original name, <code>src</code>, is unlinked from the
|
|
group graph and the new name, <code>dst</code>, is inserted
|
|
as an atomic operation. Both names are interpreted relative
|
|
to <code>loc_id</code>, which is either a file or a group
|
|
identifier.
|
|
<dt><strong>Warning:</strong>
|
|
<dd>Exercise care in moving groups as it is possible to render data in
|
|
a file inaccessible with <code>H5Gmove</code>.
|
|
See <a href="Groups.html#H5GUnlinkToCorrupt">The Group Interface</a>
|
|
in the <cite>HDF5 User's Guide</cite>.
|
|
<dt><strong>Parameters:</strong>
|
|
<dl>
|
|
<dt><em>hid_t</em> <code>loc_id</code>
|
|
<dd>IN: File or group identifier.
|
|
<dt><em>const char</em> <code>*src</code>
|
|
<dd>IN: Object's original name.
|
|
<dt><em>const char</em> <code>*dst</code>
|
|
<dd>IN: Object's new name.
|
|
</dl>
|
|
<dt><strong>Returns:</strong>
|
|
<dd>Returns a non-negative value if successful;
|
|
otherwise returns a negative value.
|
|
<dt><strong>Non-C API(s):</strong>
|
|
<dd><a href="fortran/h5g_FORTRAN.html#h5gmove_f"
|
|
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
|
|
<!--
|
|
<img src="Graphics/Java.gif">
|
|
<img src="Graphics/C++.gif">
|
|
-->
|
|
</dl>
|
|
|
|
|
|
<hr>
|
|
<dl>
|
|
<dt><strong>Name:</strong> <a name="Group-GetObjinfo">H5Gget_objinfo</a>
|
|
<dt><strong>Signature:</strong>
|
|
<dd><em>herr_t</em> <code>H5Gget_objinfo</code>(<em>hid_t</em> <code>loc_id</code>,
|
|
<em>const char *</em><code>name</code>,
|
|
<em>hbool_t</em> <code>follow_link</code>,
|
|
<em>H5G_stat_t *</em><code>statbuf</code>
|
|
)
|
|
<dt><strong>Purpose:</strong>
|
|
<dd>Returns information about an object.
|
|
<dt><strong>Description:</strong>
|
|
<dd><code>H5Gget_objinfo</code> returns information about the
|
|
specified object through the <code>statbuf</code> argument.
|
|
<code>loc_id</code> (a file or group identifier) and
|
|
<code>name</code> together determine the object.
|
|
If the object is a symbolic link and <code>follow_link</code> is
|
|
zero (<code>0</code>), then the information returned is that for the link itself;
|
|
otherwise the link is followed and information is returned about
|
|
the object to which the link points.
|
|
If <code>follow_link</code> is non-zero but the final symbolic link
|
|
is dangling (does not point to anything), then an error is returned.
|
|
The <code>statbuf</code> fields are undefined for an error.
|
|
The existence of an object can be tested by calling this function
|
|
with a null <code>statbuf</code>.
|
|
<p>
|
|
<code>H5Gget_objinfo</code> fills in the following data structure:
|
|
<pre>
|
|
typedef struct H5G_stat_t {
|
|
unsigned long fileno[2];
|
|
unsigned long objno[2];
|
|
unsigned nlink;
|
|
int type;
|
|
time_t mtime;
|
|
size_t linklen;
|
|
} H5G_stat_t
|
|
</pre>
|
|
The <code>fileno</code> and <code>objno</code> fields contain
|
|
four values which uniquely itentify an object among those
|
|
HDF5 files which are open: if all four values are the same
|
|
between two objects, then the two objects are the same
|
|
(provided both files are still open).
|
|
<ul>
|
|
<li>Note that if a file is closed and re-opened, the
|
|
value in <code>fileno</code> will change.
|
|
<li>If a VFL driver either does not or cannot detect that
|
|
two <code>H5Fopen</code> calls referencing the same file
|
|
actually open the same file, each will get a different
|
|
<code>fileno</code>.
|
|
</ul>
|
|
<p>
|
|
The <code>nlink</code> field is the number of hard links to
|
|
the object or zero when information is being returned about a
|
|
symbolic link (symbolic links do not have hard links but
|
|
all other objects always have at least one).
|
|
The <code>type</code> field contains the type of the object,
|
|
one of
|
|
<code>H5G_GROUP</code>,
|
|
<code>H5G_DATASET</code>,
|
|
<code>H5G_LINK</code>, or
|
|
<code>H5G_TYPE</code>.
|
|
The <code>mtime</code> field contains the modification time.
|
|
If information is being returned about a symbolic link then
|
|
<code>linklen</code> will be the length of the link value
|
|
(the name of the pointed-to object with the null terminator);
|
|
otherwise <code>linklen</code> will be zero.
|
|
Other fields may be added to this structure in the future.
|
|
<dt><strong>Note:</strong>
|
|
<dd>Some systems will be able to record the time accurately but
|
|
unable to retrieve the correct time; such systems (e.g., Irix64)
|
|
will report an <code>mtime</code> value of 0 (zero).
|
|
<dt><strong>Parameters:</strong>
|
|
<dl>
|
|
<dt><em>hid_t</em> <code>loc_id</code>
|
|
<dd>IN: File or group identifier.
|
|
<dt><em>const char</em> <code>*name</code>
|
|
<dd>IN: Name of the object for which status is being sought.
|
|
<dt><em>hbool_t</em> <code>follow_link</code>
|
|
<dd>IN: Link flag.
|
|
<dt><em>H5G_stat_t</em> <code>*statbuf</code>
|
|
<dd>OUT: Buffer in which to return information about the object.
|
|
</dl>
|
|
<dt><strong>Returns:</strong>
|
|
<dd> Returns a non-negative value if successful, with the fields of
|
|
<code>statbuf</code> (if non-null) initialized.
|
|
Otherwise returns a negative value.
|
|
<!--
|
|
<dt><strong>Non-C API(s):</strong>
|
|
<dd><a href="fortran/h5g_FORTRAN.html#h5gget_objinfo_f"
|
|
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
|
|
-->
|
|
<!--
|
|
<img src="Graphics/Java.gif">
|
|
<img src="Graphics/C++.gif">
|
|
-->
|
|
</dl>
|
|
|
|
|
|
<hr>
|
|
<dl>
|
|
<dt><strong>Name:</strong> <a name="Group-GetLinkval">H5Gget_linkval</a>
|
|
<dt><strong>Signature:</strong>
|
|
<dd><em>herr_t</em> <code>H5Gget_linkval</code>(<em>hid_t</em> <code>loc_id</code>,
|
|
<em>const char *</em><code>name</code>,
|
|
<em>size_t</em> <code>size</code>,
|
|
<em>char *</em><code>value</code>
|
|
)
|
|
<dt><strong>Purpose:</strong>
|
|
<dd>Returns the name of the object that the symbolic link points to.
|
|
<dt><strong>Description:</strong>
|
|
<dd><code>H5Gget_linkval</code> returns <code>size</code>
|
|
characters of the name of the object that the symbolic link <code>name</code> points to.
|
|
<p>
|
|
The parameter <code>loc_id</code> is a file or group identifier.
|
|
<p>
|
|
The parameter <code>name</code> must be a symbolic link pointing to
|
|
the desired object and must be defined relative to <code>loc_id</code>.
|
|
<p>
|
|
If <code>size</code> is smaller than the size of the returned object name, then
|
|
the name stored in the buffer <code>value</code> will not be null terminated.
|
|
<p>
|
|
This function fails if <code>name</code> is not a symbolic link.
|
|
The presence of a symbolic link can be tested by passing zero for
|
|
<code>size</code> and NULL for <code>value</code>.
|
|
<p>
|
|
This function should be used only after <code>H5Gget_objinfo</code> has been called
|
|
to verify that <code>name</code> is a symbolic link.
|
|
<dt><strong>Parameters:</strong>
|
|
<dl>
|
|
<dt><em>hid_t</em> <code>loc_id</code>
|
|
<dd>IN: Identifier of the file or group.
|
|
<dt><em>const char *</em><code>name</code>
|
|
<dd>IN: Symbolic link to the object whose name is to be returned.
|
|
<dt><em>size_t</em> <code>size</code>
|
|
<dd>IN: Maximum number of characters of <code>value</code>
|
|
to be returned.
|
|
<dt><em>char *</em><code>value</code>
|
|
<dd>OUT: A buffer to hold the name of the object being sought.
|
|
</dl>
|
|
<dt><strong>Returns:</strong>
|
|
<dd>Returns a non-negative value, with the link value in <code>value</code>,
|
|
if successful.
|
|
Otherwise returns a negative value.
|
|
<dt><strong>Non-C API(s):</strong>
|
|
<dd><a href="fortran/h5g_FORTRAN.html#h5gget_linkval_f"
|
|
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
|
|
<!--
|
|
<img src="Graphics/Java.gif">
|
|
<img src="Graphics/C++.gif">
|
|
-->
|
|
</dl>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<hr>
|
|
<dl>
|
|
<dt><strong>Name:</strong> <a name="Group-SetComment">H5Gset_comment</a>
|
|
<dt><strong>Signature:</strong>
|
|
<dd><em>herr_t</em> <code>H5Gset_comment</code>(<em>hid_t</em> <code>loc_id</code>,
|
|
<em>const char *</em><code>name</code>,
|
|
<em>const char *</em><code>comment</code>
|
|
)
|
|
<dt><strong>Purpose:</strong>
|
|
<dd>Sets comment for specified object.
|
|
<dt><strong>Description:</strong>
|
|
<dd><code>H5Gset_comment</code> sets the comment for the the
|
|
object <code>name</code> to <code>comment</code>.
|
|
Any previously existing comment is overwritten.
|
|
<p>
|
|
If <code>comment</code> is the empty string or a
|
|
null pointer, the comment message is removed from the object.
|
|
<p>
|
|
Comments should be relatively short, null-terminated,
|
|
ASCII strings.
|
|
<p>
|
|
Comments can be attached to any object that has an object header,
|
|
e.g., data sets, groups, named data types, and data spaces, but
|
|
not symbolic links.
|
|
<dt><strong>Parameters:</strong>
|
|
<dl>
|
|
<dt><em>hid_t</em> <code>loc_id</code>
|
|
<dd>IN: Identifier of the file or group.
|
|
<dt><em>const char *</em><code>name</code>
|
|
<dd>IN: Name of the object whose comment is to be set or reset.
|
|
<dt><em>const char *</em><code>comment</code>
|
|
<dd>IN: The new comment.
|
|
</dl>
|
|
<dt><strong>Returns:</strong>
|
|
<dd>Returns a non-negative value if successful;
|
|
otherwise returns a negative value.
|
|
<dt><strong>Non-C API(s):</strong>
|
|
<dd><a href="fortran/h5g_FORTRAN.html#h5gset_comment_f"
|
|
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
|
|
<!--
|
|
<img src="Graphics/Java.gif">
|
|
<img src="Graphics/C++.gif">
|
|
-->
|
|
</dl>
|
|
|
|
|
|
<hr>
|
|
<dl>
|
|
<dt><strong>Name:</strong> <a name="Group-GetComment">H5Gget_comment</a>
|
|
<dt><strong>Signature:</strong>
|
|
<dd><em>herr_t</em> <code>H5Gget_comment</code>(<em>hid_t</em> <code>loc_id</code>,
|
|
<em>const char *</em><code>name</code>,
|
|
<em>size_t</em> <code>bufsize</code>,
|
|
<em>char *</em><code>comment</code>
|
|
)
|
|
<dt><strong>Purpose:</strong>
|
|
<dd>Retrieves comment for specified object.
|
|
<dt><strong>Description:</strong>
|
|
<dd><code>H5Gget_comment</code> retrieves the comment for the the
|
|
object <code>name</code>. The comment is returned in the buffer
|
|
<code>comment</code>.
|
|
<p>
|
|
At most <code>bufsize</code> characters, including a null
|
|
terminator, are copied. The result is not null terminated
|
|
if the comment is longer than the supplied buffer.
|
|
<p>
|
|
If an object does not have a comment, the empty string
|
|
is returned.
|
|
<dt><strong>Parameters:</strong>
|
|
<dl>
|
|
<dt><em>hid_t</em> <code>loc_id</code>
|
|
<dd>IN: Identifier of the file or group.
|
|
<dt><em>const char *</em><code>name</code>
|
|
<dd>IN: Name of the object whose comment is to be set or reset.
|
|
<dt><em>size_t</em> <code>bufsize</code>
|
|
<dd>IN: Anticipated size of the buffer required to hold
|
|
<code>comment</code>.
|
|
<dt><em>char *</em><code>comment</code>
|
|
<dd>OUT: The comment.
|
|
</dl>
|
|
<dt><strong>Returns:</strong>
|
|
<dd>Returns the number of characters in the comment,
|
|
counting the null terminator, if successful; the value
|
|
returned may be larger than <code>bufsize</code>.
|
|
Otherwise returns a negative value.
|
|
<dt><strong>Non-C API(s):</strong>
|
|
<dd><a href="fortran/h5g_FORTRAN.html#h5gget_comment_f"
|
|
target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
|
|
<!--
|
|
<img src="Graphics/Java.gif">
|
|
<img src="Graphics/C++.gif">
|
|
-->
|
|
</dl>
|
|
|
|
|
|
<hr>
|
|
<center>
|
|
<table border=0 width=98%>
|
|
<tr><td valign=top align=left>
|
|
<a href="H5.intro.html">Introduction to HDF5</a> <br>
|
|
<a href="H5.user.html">HDF5 User Guide</a> <br>
|
|
<a href="index.html">Other HDF5 documents and links</a> <br>
|
|
<!--
|
|
<a href="Glossary.html">Glossary</a><br>
|
|
-->
|
|
</td>
|
|
<td valign=top align=right>
|
|
And in this document, the
|
|
<a href="RM_H5Front.html">HDF5 Reference Manual</a>
|
|
<br>
|
|
<a href="RM_H5.html">H5</a>
|
|
<a href="RM_H5A.html">H5A</a>
|
|
<a href="RM_H5D.html">H5D</a>
|
|
<a href="RM_H5E.html">H5E</a>
|
|
<a href="RM_H5F.html">H5F</a>
|
|
H5G
|
|
<a href="RM_H5I.html">H5I</a>
|
|
<a href="RM_H5P.html">H5P</a>
|
|
<br>
|
|
<a href="RM_H5R.html">H5R</a>
|
|
<a href="RM_H5S.html">H5S</a>
|
|
<a href="RM_H5T.html">H5T</a>
|
|
<a href="RM_H5Z.html">H5Z</a>
|
|
<a href="Tools.html">Tools</a>
|
|
<a href="PredefDTypes.html">Datatypes</a>
|
|
</td></tr>
|
|
</table>
|
|
</center>
|
|
<hr>
|
|
|
|
|
|
<address>
|
|
<a href="mailto:hdfhelp@ncsa.uiuc.edu">HDF Help Desk</a>
|
|
|
|
<br>
|
|
Last modified: 18 April 2002
|
|
<br>
|
|
Describes HDF5 Release 1.5, Unreleased Development Branch
|
|
|
|
</body>
|
|
</html>
|